Telnet. One of the oldest network protocols

Telnet is a protocol used on the Internet or local area networks to provide a bidirectional interactive text-oriented communication facility using a virtual terminal connection. Telnet was developed in 1969 and it is still widely used today for configuring network devices.

Why worry about Telnet?

Because Telnet is an unencrypted protocol, session traffic will reveal command line interface (CLI) command sequences appropriate for the make and model of the device. CLI strings may reveal login procedures, presentation of user credentials, commands to display boot or running configuration, copying files and creation or destruction of GRE tunnels, etc…

A recent cyber briefing from the UK based National Cyber Security Centre (NCSC) recommends that you check your network for any devices running unencrypted management protocols such as:

• Telnet
• Hypertext Transport Protocol (HTTP, port 80)
• Simple Network Management Protocol (SNMP, ports 161/162)
• Cisco Smart Install (SMI port 4786)

If these services are in use the NCSC recommends the following:

• Do not allow unencrypted (i.e. plaintext) management protocols (e.g. Telnet) to enter an organisation from the Internet. When encrypted protocols such as SSH, HTTPS, or TLS are not possible, management activities from outside the organisation should be done through an encrypted Virtual Private Network (VPN) where both ends are mutually authenticated.
• Do not allow Internet access to the management interface of any network device. The best practice is to block Internet-sourced access to the device management interface and restrict device management to an internal trusted and whitelisted host or LAN. If access to the management interface cannot be restricted to an internal trusted network, restrict remote management access via encrypted VPN capability where both ends are mutually authenticated. Whitelist the network or host from which the VPN connection is allowed, and deny all others.
• Disable legacy unencrypted protocols such as Telnet and SNMPv1 or v2c. Where possible, use modern encrypted protocols such as SSH and SNMPv3. Harden the encrypted protocols based on current best security practice. The NCSC and DHS strongly advise owners and operators to retire and replace legacy devices that cannot be configured to use SNMP V3.
• Immediately change default passwords and enforce a strong password policy. Do not reuse the same password across multiple devices. Each device should have a unique password. Where possible, avoid legacy password-based authentication, and implement two-factor authentication based on public-private keys.

Using network traffic analysis to detect Telnet activity

As I mentioned previously, Telnet normally runs over TCP port 23. However, you can configure Telnet to run over any port and so you cannot just watch out for network traffic running on TCP port 23. You must be able to monitor all traffic and pick out the Telnet traffic by using some form of application detection.

Wireshark is one of the most popular traffic analysis tools and has the capability to detect Telnet traffic as it has access to packet payloads which can be used for application identification. Flow based tools (NetFlow, SFlow) are not suitable for detecting Telnet activity as they are not application aware. Wireshark is fine for low network traffic volumes or if you have a PCAP file that you want to analyze.

If you want to get continous monitoring in place then you need to look at setting up a data source such as a SPAN, mirror port or network TAP. Once you have a data source then you need a commercial network traffic analysis system in place like our own LANGuardian. It has an application recognition engine which can report on any Telnet activity no matter what port it is running over.

Using LANGuardian to detect Telnet activity on your network

LANGuardian uses Content-Based Application Recognition (CBAR) to identify what applications are running on your network. With support for hundreds of the most common applications and protocols, and a unique deep packet inspection algorithm, CBAR delivers greater accuracy and fewer false positives than other approaches to application recognition.

A sample output of this Applications in Use report is shown below. Here we can see that some Telnet activity has been detected.

Drilling down on this Telnet traffic then reveals that Telnet services are active on two seperate ports on a single server as you can see in the image below. LANGuardian can also alert you if a new server port becomes active which is useful for watching out for new activations of Telnet services on your network.

You can download a 30 day trial of LANGuardian from here and use it to detect any device running Telnet services on your network. You do not need any logs or client software. Just setup a SPAN or mirror port and you can passively monitor activity at your network edge and east west traffic moving within your network.

Weak SSL/TLS encryption. Why worry?

A Google search for “GDPR countdown clock” yielded 18,900 results for me this morning so probably the last thing we need to consider is another countdown clock, but here is one for PCI compliance anyway.

The clock highlights 30 June 2018,  an important deadline for online security and network Administrators; a date from which older versions of TLS and all SSL should be confined to history for PCI compliant networks. From 30 June 2018, to be compliant with PCI DSS 3.2, SSL and “early versions” of TLS protocol should be eliminated from use (with some exceptions for POS terminals). This is because PCI requires the use of “strong encryption” and known weakness in all SSL, some TLS versions and some cipher suites mean they fail the ‘strong encryption’ standard.

“Early TLS” is defined as anything before TLS 1.1; however TLS 1.1 is also vulnerable as it allows use of bad ciphers; so TLS 1.2 is a better choice. Along with this version change, the ciphers that are used by SSL/TLS need to be carefully managed too. The ciphers and the SSL/TLS protocol versions are separate, but not completely independent of each other.

Even if you don’t care about PCI compliance, this is important for all networks running SSL/TLS; that includes your own networks, partner or client networks, that interact with your infrastructure. GDPR regulations (article 31) require use of “state of the art” technical and organisational measures to ensure security. While the GDPR language lacks specifics, we can look to PCI 3.2 and NIST guidelines (800-52 Rev 1) which strongly recommend use of TLS1.2 only, to know that SSL, TLS1.0 and TLS1.1 are not state of the art, and so fail the GDPR test. The NIST draft for 800-52 Rev 2 explicitly prohibits use of TLS 1.1.

What’s the problem, SSL provides encryption doesn’t it?

Since the mid 1990’s, SSL/TLS encryption has underpinned much of online security and is the defacto choice for encrypting our web based online shopping and payment transactions. SSL/TLS keeps our transactions private and unaltered. However, researchers and attackers have identified and published weaknesses in the aging versions of the protocols, from SSL2.0, SSL3.0, TLS1.0 and TLS1.1. and in the ciphers that they use. There are three sources of weakness here to be aware of:

1. Some weaknesses are in the protocol implementation itself, for example Heartbleed exploited a read buffer overflow in OpenSSL’s implementation of in the heartbeat extension. This allowed attacking clients to read private key information from the server.
2. Other weaknesses are in the ciphers supported SSL/TLS. For example, increased computation along with the increased volumes of data being transferred, mean that 3DES cipher can be compromised in about 1 hour, using the Sweet 32 attacks. RC4 can also be compromised by brute force attacks. These weaker ciphers are supported by all versions of SSL/TLS up to version 1.2. However, newer. stronger ciphers such as AES are only supported by newer versions of SSL/TLS. So, use new version of TLS to enable use of stronger ciphers.
3. Weakness in the protocol itself

Even if properly implemented, according to the spec, with good ciphers, TLS1.1 is still vulnerable. The PRF (pseudorandom function) is based on broken cryptographic hashes MD5 or SHA1 and its use of ciphers in CBC mode is insecure.

There are no available fixes for these weakness, so the only avenue to remain secure is to use the newer more robust versions.

TLS1.3, the newest, most secure version of TLS resolves the known weakness with the protocol, prohibits use of weak ciphers and has a much shorter setup time. TLS1.3 was in draft form when PCI 3.2 was adopted, so it isn’t mentioned in the PCI 3.2 document (TLS1.3 was formally adopted in March 2018. Mandating use of TLS1.3 at this stage could lead to interoperability problems).

Using Network Monitoring for SSL/TLS analysis

There are various techniques for identifying the SSL/TLS versions and ciphers that servers will support, such as nmap or just running Openssl from the command line. However, this requires that periodic checks are carried, the full inventory is always known, and you have access to scan the network. The PCI Security Standards Council emphasise the important of ensuring adherence to standards at all times and not just once per year to close audit requirements!

Continuous adherence is just good business and security practice and essentially points to continuous monitoring, rather than scheduled pen testing efforts. If you monitor network traffic within your network and perform packet analysis at session startup time, it’s possible to view the SSl/TLS versions and cipher used, as well as the certificates used on encrypted protocols (excluding TLS 1.3) .

You can do this without any access to the servers (i.e you can do it from the client or partner network) and without terminating any of the SSL/TLS sessions (i.e you don’t have to use man in the middle devices). This is possible as the opening salvos in SSL/TLS session establishment happen in the clear. The protocol negotiation, cipher choice and certificate exchange are all readable. Add to this the Server Name Indication (SNI) extension and a packet monitoring application can extract a lot of useful information about the nature of encrypted sessions on the network.

LANGuardian 14.4.1 includes features that are useful for monitoring the status of SSL/TLS on your network.

NetFort LANGuardian is deep-packet inspection software that monitors network and user activity passively via a SPAN\Mirror port or TAP. Here are a couple of use cases which cover how it can be used to detect the use of weak SSL/TLS encryption on your network.

The first is an inventory of SSL/TLS servers. Built from passive traffic analysis, this shows every SSL/TLS server, that has generated traffic on the network. The server can be internal or external (e.g a HTTPS website). The inventory report for each server shows some details of the server certificate, with expiry date and signature algorithm. It also shows the SSL/TLS protocol versions that the server has used to communicate with clients. Issues are highlighted in red, such as expired certificates or weak certificate signature algorithms, such as SHA1. A set of filters help identify conditions, such as use of SHA1 and help identify servers that need configuration or updates.

Filters for reporting on SSL/TLS Sever Inventory

Report on a single SSL server, showing expired certificate, weak protocol used, weak SHA1 algorithm

The other feature is a report on all the SSL/TLS sessions that have occurred on the network. This report (and its drilldowns), identifies all clients and servers that use SSL/TLS encryption, identifying the version of SSL/TLS used and the cipher that is used. Filters can be used to focus on versions of SSL/TLS, identify where SSL3.0 is used for example, or identify where any communication occurs that does not use TLS1.2.

Report showing use of weak SSL/TLS versions

Report drilldown showing cipher used by weak SSL3.0 session

A filter is also provided for the ciphers that are used. Ciphers suites have a specific naming scheme, which identity various attributes of the cipher used, viz:

TLS_KeyExchangeAlg_WITH_EncryptionAlg_MessageAuthenticationAlg.

For example, the cipher TLS_RSA_WITH_AES_128_CBC_SHA

is for use with TLS, using RSA for key exchange, AES 128 bit encryption, with SHA digests.

Report showing use of 3DES cipher

Filter support for SSL/TLS Versions and Ciphers

The list of supported ciphers for various versions of SSL/TLS is extensive (many hundreds) and there’s a balance between security and interoperability to consider when choosing which ciphers should be supported. Recommendations generally are to avoid RC4 and 3DES.

Continuous Network Monitoring is a useful tool for ensuring your network is operating to whatever standards or compliance regulations the you are required to adhere. Without using man in the middle decryption devices, it is possible to learn about the activity on your network.

Video Guide: How to detect weak SSL/TLS encryption on your network

Here are some links for further reading.

https://www.pcisecuritystandards.org/pdfs/PCI_SSC_Migrating_from_SSL_and_Early_TLS_Resource_Guide.pdf

https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-52r1.pdf

https://tools.ietf.org/html/rfc7540#appendix-A

You can download a 30 day trial of LANGuardian from here and use it to detect the use of weak SSL/TLS encryption on your network. You do not need any logs or client software. Just setup a SPAN or mirror port and you can passively monitor activity at your network edge and horizontal traffic moving within your network.

LANGuardian 14.4.1

NetFort are delighted to announce the availability of the latest major LANGuardian release, V14.4.1. This release introduces some changes and new features to help with compliance monitoring, including a new compliance section presents reports for monitoring technical security compliance with CIS CSC 20 and GDPR. Highlights of this release include:

• SMB fileshare alerts on failed attempts to map network shares, create or read files and folders.
• Encrypted sessions analysis of SSL/TLS/QUIC versions and ciphers used
• Detect new server ports in use on your network
• New Applications in use black/whitelist.
• Allign report names more with compliance standards.

SMB fileshare alerts on failed attempts to map network shares, create or read files and folders

For some time now we have included a file activity monitoring feature in our LANGuardian product. It passively generates an audit trail of file and folder activity using network traffic as a data source. LANGuardian 14.4.1 extends this monitoring to now include the capture of failed access attempts. Many compliance standards require this so that you can detect anomalous activity where a user or device is attempting to access sensitive data.

You can read more about this feature in this blog post which looks at why is it important to monitor for failed access attempts. The screen shot below shows an example of the report output.

Encrypted sessions analysis of SSL/TLS/QUIC versions and ciphers used.

Since the mid 1990’s, SSL/TLS encryption has underpinned much of online security and is the defacto choice for encrypting our web based online shopping and payment transactions. SSL/TLS keeps our transactions private and unaltered. However, researchers and attackers have identified and published weaknesses in the aging versions of the protocols, from SSL2.0, SSL3.0, TLS1.0 and TLS1.1. and in the ciphers that they use.

LANGuardian 14.4.1 includes features that are useful for monitoring the status of SSL/TLS on your network. They include:

• Inventory of SSL/TLS servers
• Report on all the SSL/TLS sessions that have occurred on the network
• A filter is also provided for the ciphers that are used

Learn more in this blog post which looks at how to detect weak SSL/TLS encryption on your network. The sample report below shows how LANGuardian can be used to show use of weak SSL/TLS versions.

Detect new server ports in use on your network

Opening new ports on a server increases that servers attack surface. Keeping the attack surface as small as possible is a basic security measure. New ports become active if you install new software or if you enable a new service on the server. For important servers on your network you should have an inventory of what applications or services are running so that changes can be detected.

If compliance standards such as GDPR are a concern then server monitoring is not just a nice to have, it becomes mandatory. You must maintain an inventory of who is connecting to what if you store sensitive or personal data. LANGuardian 14.4.1 now logs certain information when a port becomes active on a server for the first time. Read more in this blog post which looks at how to detect new server ports in use on your network using LANGuardian. The screen shot below shows an example of the report output.

Applications in use. Build white or black lists

LANGuardian uses an advanced application recognition engine to report on network activity. Instead of matching up port numbers with application names, it analyzes packet payloads to work out what applications are in use. LANGuardian 14.4.1 now includes new report filters which allow you to build lists of white or blacklists. You can then use these lists to detect new applications in critical areas such as your server VLAN.

You can access these new filters in the Applications in Use report. Click on the Protocol dropdown to start to build application lists.

Align report names more with compliance standards.

LANGuardian 14.4.1 includes a new compliance section which groups reports for monitoring technical security compliance with CIS CSC 20 and GDPR standards. Many reports have been renamed so that they are more aligned with compliance standards. For example Top DNS Servers was renamed to DNS Servers. A full list of reports which were renamed can be found within the 14.4.1 release notes.

Video Guide: LANGuardian 14.4.1

Why is it important to monitor for failed access attempts?

For some time now we have included a file activity monitoring feature in our LANGuardian product. It passively generates an audit trail of file and folder activity using network traffic as a data source. All you need to do is monitor network traffic going to and from your file servers and you can easily see who is doing what with your files and folders. The image below shows an output of a sample report.

With the release of LANGuardian 14.4.1 we can now report on successful and failed access attempts to network file shares. The failed access attempts can be viewed in report format or they can also trigger alerts via email or SYSLOG.

For many compliance standards such as GDPR and CIS CSC 20 you also need to monitor for failed access attempts.  This is useful for generating alerts on anomalous activity where a user or device is attempting to access sensitive data. When it comes to GDPR and failed access attempts, this is what you need to focus on and how LANGuardian can help:

A closer look at the LANGuardian failed access reports

The image below shows a sample output. Here can see some failed file open attempts originating from client 192.168.127.237. Drilling down further will show the date and time that this event was triggered and you can also get associated usernames if you have configured the Active Directory integration.

Video Guide: Generating an Audit Trail of Failed Access Attempts to Files or Folders

You can download a 30 day trial of LANGuardian from here and use it to monitor, track file and folder activity on your network. You do not need any logs or client software. Just setup a SPAN or mirror port and you can passively monitor activity to and from your file servers.

What is a server?

In client-server processes that use Transmission Control Protocol/Internet Protocol (TCP/IP) or User Datagram Protocol (UDP), the client initiates communication with a server through one of the many well-known ports. In computer networking, a port is an endpoint of communication in an operating system. While the term is also used for physical devices, in software it is a logical construct that identifies a specific process or a type of network service. For example, HTTP traffic typically uses TCP port 80.

What makes a server is that it is the one that accepts a connection from a client. Typically, this port is left open or running so that clients can connect at any time. It is good security policy to restrict the number of ports which are open on a server. Each open port is a way to gain access to that server. In recent times several Ransomware variants spread around networks by exploiting a vulnerability in SMBv1. Infected clients searched for any host with TCP port 445 active and then tried to communicate using the SMBv1 protocol. The image below shows the handshake that makes up a TCP connection request.

Why worry about new server ports?

As I mentioned previously, opening new ports on a server increases that servers attack surface. Keeping the attack surface as small as possible is a basic security measure. New ports become active if you install new software or if you enable a new service on the server. Enabling something such as RDP (remote desktop protocol) can compromise the entire server and provides a way for data to be transferred off.

For important servers on your network you should have an inventory of what applications or services are running so that changes can be detected. You can do this by constantly polling the server on every port number or monitor network traffic going to and from the server. The polling method can be problematic as you will need to constantly bombard the server with connection requests and you may miss something if the application or service was only active for a short time.

If compliance standards such as GDPR are a concern then server monitoring is not just a nice to have, it becomes mandatory. You must maintain an inventory of who is connecting to what if you store sensitive or personal data.

Detecting new server ports by monitoring network traffic

If you monitor network traffic going to and from your important servers you can build up an inventory of what ports are open without the need to interact with the servers. One way to do this is to use a SPAN or mirror port to get a copy of the network traffic going to and from your servers. You would then need a network traffic analysis tool such as LANGuardian to process this data and extract the relevant metadata from the network packets. The image below shows an example of what would be required. The four servers can be monitored via a single SPAN or mirror port.

Detecting new server ports with LANGuardian

Once you have your SPAN or mirror port in place and you have a LANGuardian installed monitoring the network traffic you can start to build up an inventory of new server ports. Type “server ports” into the search field at the top of the LANGuardian web interface and select “Network Events (New Server Ports)“. Pick a date range and then see if any new server ports became active during the selected time period. The image below shows a sample of the report output.

The report contains a number of fields

1. Sensor: LANGuardian can process traffic from multiple network points via remote sensors. The sensor field shows which sensor detected activity on the new server port.
2. Server address: The network device which is accepting client requests.
3. Port: Which port the server is listening on. Some ports will be labelled.
4. When detected: The date and time when communication was first detected.
5. Server reply: This is section of the servers reply to a client. In some cases it is human readable in others it is just a binary string of random characters.

The video below shows an example of this report in action.

It is back to work and school this week, following the most severe blizzard in years to hit Ireland, storm Emma (Emma, who decides the name?). The country was under the highest weather warning, a red alert, as the worst snow in 35 years swept north across the island. All shops were closed because of the weather and because they had no fresh meat, bread or milk left!  There seemed to be more talk regarding the lack of bread on shelves than the weather which is really unusual for the Irish. I saw some students walking home from the stores with cases of beer, pizza, beer, movies, no mortgage to pay, no worries, happy days, good for them!

Anyway, this storm has reminded me of another one that is on the way, and will also have a severe impact, the ‘GDPR’ storm.  GDPR is a hot topic for many people and organizations all over the world at the moment, not just across the EU but for also for ‘non-EU’ companies, even if they are not based in the EU. It is such an important market and as a result, they have EU ‘data’ and they are impacted.

It is such an important market and as a result, many organizations have EU ‘data’ and they are impacted. The port in this storm for many companies may be the CIS CSC 20.

Obviously, there is also a lot of hype and companies jumping on the bandwagon. Some of our customers have mentioned that they are sick of receiving sales calls from vendors, consultants, etc at this stage on the subject.

We in NetFort have been contacted by our customers, mostly our Irish and UK ones to date, asking us how we can help. ‘We have already purchased a LANGuardian, have been a good customer for years, we want to buy as few tools as possible, how can you help?’ Makes sense, most companies already have too many point security solutions and are trying to consolidate, NOT buy more.

We have also secured some new EU customers in central Europe. One for example, when asked why they purchased, came back with the following interesting information:

“On our side, our GDPR” requirements are (so far):

• Who is doing what on any shared file?
• Who is sending or receiving a file on the Internet?
• What is done on a database (SQL query is fine)?
• What rights are given to some user?
• What Admin are doing (reading CEO files or mail for example)?
• What email is sent, to whom, with an attachment- for SMTP’
• Some kind of IDS (have we been attacked) from either the internal network and the outside’

The image below shows a section from our CIS CSC 20 reports which we built using customer feedback like that shown above.

So we have taken the approach of firstly trying to work with and help our current customers and taking it from there.

Our LANGuardian  analyses raw network traffic or wire data, extracts application specific metadata and integrates with Active Directory to enrich the traffic metadata and add usernames. It enables visibility, drill down, context into both Internet and internal network user and device activity including shared Data (file shares and SQL databases)  Inventory, Users, and Applications.  The LANGuardian is ideal for continuous monitoring, troubleshooting, forensics and as result an ideal data source or tool to help demonstrate visibility, control, and compliance. It retains an audit trail of network activity very cost effectively for long periods but we needed to convince ourselves first of the compliance and GDPR usefulness, then discuss it with our customers and get their reaction.

Our or my first piece of learning was that GDPR is very vague, time-consuming and difficult to read and understand. I’m an engineer, I want hard facts, the detail I can read and believe in. I understand GDPR is still in its infancy but at the moment it is almost so vague it is frightening a lot of organizations and as a result, they are waiting to see what will happen. Risky approach.

From a security perspective, Article 32 specifically compels companies to look at existing best practices. For example, The UK’s National Cyber Security Centre “10 Steps to Cyber Security’ or ISO 27001 or the CIS CSC 20 Security Controls.  In our opinion, one very practical and detailed option is the CIS Critical Security Controls, originally the SANS Top 20.  Lot of good information here: https://www.cisecurity.org/controls/

So we have studied them and tried to understand the detail. There is a lot of good practical information, readable which is critical but also realistic. GDPR aside, organizations should use these or an equivalent as guidelines, a good checklist. Recently I have met a number of our customers face to face and made a presentation on the CIS CSC 20 and how they can help. I wasn’t trying to sell to them, they are already customers. Just trying to have a discussion and get their reaction.

I was surprised to discover that about 50% of them to date had been studying the CIS CSC 20 and the current goal was to target the top 5 and be able to demonstrate compliance with these by May:

1. CSC 1, Inventory of Authorized and Unauthorized Devices
2. CSC 2, Inventory of Authorized and Unauthorized Software
3. CSC 3, Secure Configurations for Hardware and Software on Mobile Devices, Laptops, Workstations, and Servers
4. CSC 4, Continuous Vulnerability Assessment and Remediation
5. CSC 5, Controlled Use of Administrative Privileges

Seems like a good approach to us, take it step by step, be realistic. Be able to demonstrate that you are trying, taking it seriously, doing your best to be compliant. The goal is not just a checklist, it is to improve security and AVOID a breach. Everybody wins.

So now we ARE on a mission, on the CIS CSC 20 bandwagon because they are a very good practical set of security guidelines and realistic for organizations of all sizes.  We are trying to leverage them and show how our LANGuardian internal visibility and continuous monitoring of network and user activity can try and help our customers.

We now have a GDPR and CIS CSC 20 tab on our LANGuardian system, access it directly here.

Stay tuned to this blog for more and more practical information and learnings.

John Brosnan

CEO, NetFort

HTTP Background

Designed in the early 1990s, HTTP is an application layer protocol that is sent over TCP, though any reliable transport protocol could theoretically be used. Typically it uses TCP port 80 but this can be changed. Due to its extensibility, it is used to not only fetch hypertext documents, but also images and videos or to post content to servers, like with HTML form results. HTTP can also be used to fetch parts of documents to update Web pages on demand.

Google are promoting a move away from HTTP

For the past several years, Google have moved towards a more secure web by strongly advocating that sites adopt HTTPS encryption. It started back in 2014 when they announced that they were using HTTPS as a ranking signal. If you moved your site away from HTTP and onto HTTPS you would receive a tiny boost in the Google search rankings.

Beginning in July 2018 with the release of Chrome 68, Chrome will mark all HTTP sites as “not secure”. If you host your own web servers it could mean that users will be less likely to interact with them if their browsers are marking them as insecure. Now is the time to move your websites from HTTP to HTTPS.

Generating an inventory of HTTP servers using network traffic analysis.

HTTP servers normally run over TCP port 80.However, you can configure HTTP servers to run over any port so generating a list of web servers running over TCP port 80 may not result in the complete list. Another method to detect webservers would be to use a network scanning too that would check for anything listening on port 80 or other ports.

One thing to watch with the scanning approach is to make sure all servers are powered up when you run the network scan. Another issue with this approach is that you won’t be able to find out if users from outside your network are accessing these servers, you will just know that they are active.

Our recommended appoach is to monitor network traffic going to and from your web servers. You can do this by setting up a SPAN\Mirror port or by using a TAP device. If you are only concerned about users outside of your network, you just need to monitor your Internet gateway points. The video below goes through the process of getting network monitoring in place at your network edge.

Once you have a data source in place (SPAN\Mirror\TAP) you can then check for web server activity by searching for specific metadata such as a HTTP GET. For small networks you can manually do this using tools like Wireshark. For larger networks you can automate this with an application such as our own LANGuardian. It has built in web traffic decoders which can automatically build a HTTP server inventory 24/7.

Using LANGuardian to passively detect HTTP servers on your network

LANGuardian comes with an application recognition engine which can report on what applications are in use on your network. If you combine these reports with filters you can quickly find out what web servers are on your network and also which are being accessed by clients and their countries outside your network.

The image below shows an example of the output. Here we can see that we had 6 HTTP servers active on our network for the past 1 hour sample time period. Also worth noting is that some of these web servers are running on non standard ports; 8080 and 5357.

If you have a LANGuardian on your network you need to select the “Top Website Domains” report and use these filters

1. Source = External
2. Destination = Internal
3. Protocol = HTTP

Click on the image above to access this report directly on our live demo system and drill down.

Ransomware Cryptocurrency Link

During 2017 we saw advances in security tools which have meant IT and network security managers have become better equipped to deal with ransomware threats. In addition, lots of standalone programs have been made by independent researchers to decrypt files. This increased awareness of ransomware prevention (backing up files) and Ransomware detection tools has really helped to reduce the Ransomware problem.

Bitcoin is frequently associated with Ransomware as it is a popular payment type demanded by ransomware authors. There are many types of crypto currency available today which you can acquire with money or goods or you can mine them using one or more computers.

The primary purpose of mining is to allow Bitcoin nodes to reach a secure, tamper-resistant consensus. Mining is also the mechanism used to introduce Bitcoins into the system: Miners are paid any transaction fees as well as a “subsidy” of newly created coins. The image below shows an example of a large bitcoin mining rig, lots of processing power and associated cooling fans to keep it operational.

One of the new trends with Malware is the move away from data encryption to a more stealthy bitcoin mining strategy. Bitcoin mining can happen in the background. No need for any splash screens or data destruction.

Crypto Mining Malware & Association With SMBv1

Many attackers now favor anonymous cryptocurrencies, with Monero being the most prominent. Crypto currencies are popular as they are both secure, private and difficult to trace. Servers are often targeted and since many of them are not updated or patched on a regular basis, attackers have a bigger chance of success.

Recently more than 526,000 Windows hosts, mostly Windows servers, have been infected by a Monero miner known as Smominru, according to researchers at Proofpoint. It spreads using the EternalBlue exploit (CVE-2017-0144) which targeted the SMBv1 protocol.

Crypto mining malware like this covertly mines for coins using the victim’s GPU horsepower without them knowing about it. It has potential for longer-term gains. When a computer is infected many people will fail to notice fans spinning up, or computers under higher load or just plain old not responding. A lot of those people may just pass it off as “one of those things my computer does.”

How to Detect SMBv1 Use on Your Network

As I mentioned earlier, the ExternalBlue exploit is being used by a lot of attackers to install Ransomware or Crypto Miners on victims PC’s. Systems are compromised when an attacker sends specially crafted messages to a Microsoft Server Message Block 1.0 (SMBv1) server

Because of this, you need to make sure you detect SMBv1 use on your network and switch off the protocol on any systems which has it enabled. SMBv1 has been superceeded by SMBv2 and SMBv3 which are far more efficient and secure.

However, sometimes reality is more difficult than the theory. I met with some of our LANGuardian customers this week. They said that when they disabled SMBv1 on some servers they had issues with a loss in connectivity to some printers. I also had issues in my home lab where certain Android devices lost connectivity to a NAS system when SMBv1 was disabled. The easy thing to do is to re-enable SMBv1 but that will increase the attack vector of your network.

Using LANGuardian to Detect SMBv1 Use

The video below shows how a traffic analysis tool like our own LANGuardian can be used to root out SMB1 clients and servers on your network. Make sure you can detect this activity by monitoring communication between clients and servers or check each network device to see if SMBv1 is enabled.

Why worry about unauthorised DNS servers?

DNS remains a vital part of computer networking. The foundation of DNS was laid in 1983 by Paul ­Mockapetris, then at the University of Southern California, in the days of ­ARPAnet, the U.S. Defense Department research project that linked computers at a small number of universities and research institutions and ultimately led to the Internet. The system is designed to work like a telephone company’s 411 service: given a name, it looks up the numbers that will lead to the bearer of that name.

DNS was never designed as a very secure protocol and it is popular target for attackers. There are two ways DNS can be hacked: by using protocol attacks (attacks based on how DNS is actually working) or by using server attacks (attacks based on the bugs or flaws of the programs or machines running DNS services).

One of the more recent protocol attacks was the DNSChanger malware. It typically changes DNS server settings on infected computers, allowing attackers to route internet traffic through malicious servers and intercept sensitive information. There is also a similar variant targeting Apple Mac computers dubbed OSX/MaMi, an unsigned Mach-O 64-bit executable.

In both of these cases the attackers change your DNS server from 8.8.8.8 (Google) for example to one of their own DNS servers. Most of your DNS queries will be handled correctly and you will get correct IP addresses. However, for certain site like banking the attackers will direct you to a mocked up website which looks like a valid banking one. You logon details are captured once you start to interact with the site and these are then used to steal your money.

Detecting unauthorised DNS server use with LANGuardian

Our LANGuardian product includes both a DNS traffic decoder and an number of alerting features which you can use to track down unauthorised DNS server use. The image below shows an example of the DNS traffic decoder. Here we can see how LANGuardian can build up an inventory of all DNS servers and client queries to them.

Having a DNS audit trail like this will also give you the data you need to investigate other DNS issues such as cache poisoning.

How to generate alerts if a device uses an unauthorised DNS server

LANGuardian includes a customizable alerting engine where you can define whitelists of valid servers and get alerts if users try an access others. For the purposes of this example we are going to create a DNS whitelist containing these servers:

• 192.168.127.22 (hosted internally on network)
• 8.8.8.8 (google1)
• 8.8.4.4 (google2)

We then use the LANGuardian alerts configuration option to create a DNS alerting rule which would trigger if queries to other servers are detected. The screenshot below shows an example of this.

Once the rule is saved it will look like this on the LANGuardian alerts list.

Once the unauthorised DNS server alert is triggered, LANGuardian will capture certain DNS metadata like source and destination IP addresses, country where DNS server is registered and the domain names that were queried. The image below shows an example of what the alerts look like.

These alerts can also be exported as SYSLOG so that they can be processed by a blocking device such as a firewall or NAC (Network Access Control) system.

How to monitor DNS traffic

One of the best ways to monitor DNS traffic is to port mirror traffic going to and from your local DNS servers and all Internet traffic. Monitoring Internet traffic is crucial so that you can pick up on devices using external DNS servers so it is really easy to monitor network traffic on your network. Most managed switches support SPAN or mirror ports. If you have a switch that does not have any traffic monitoring options there are many alternatives for SPAN ports. The video below shows the steps needed to monitor Internet traffic and you should extend this to also monitor local DNS servers.

LANGuardian 14.4

NetFort are delighted to announce the availability of the latest major LANGuardian release, V14.4. It includes a number of major enhancements including GeoIP traffic reporting, improvements to the alerting engine and the ability to capture network traffic and generate a PCAP via any LANGuardian sensor on the network.

The main themes of this release are to improve traffic analysis, better alerting and to enhance the product so that it is better able to address compliance standards such as a CSC and GDPR. LANGuardian 14.4 includes:

• New GeoIP filtering and displays.
• New MetaData alerting GUI and rules support.
• New user credentials from SMB sessions.
• New Windows Services (DCERPC) decoder.
• New full packet capture mechanism to save PCAPs from any LANGuardian sensor.
• Improved accuracy of Google QUIC fingerprinting.
• New PDF format option for scheduled reports.

New GeoIP filtering and displays

GeoIP is a feature where IP addresses are automatically matched with the country where they are registered. This is very useful if you want to track which countries are connecting to your network or what countries clients on your network are connecting to. Use this for improving your network security or to meet data export compliance regulations, such as GDPR.

We have included two new reports which can be found under the Traffic Analysis report category.

• Top Countries by Client Location. This report shows the total bandwidth, displayed by the country location of the client.
• Top Countries by Server Location. This report shows the total bandwidth, displayed by the country location of the server.

The image below shows an example of the report output.

New MetaData alerting GUI and rules support

We regularly host customer days where users of our products can review our roadmap or try out beta versions of our software. One of the most common recent requests was a need for better alerting. Customers want an easy way to configure alerts so that they are automatically notified of security or operational events that matter to them.

LANGuardian 14.4 has an updated metaData alerting GUI and rules support, to alert on a wide range of conditions and events that LANGuardian monitors for, such as authorized applications, unknown DNS servers, inter-subnet access attempts and much more. Use this to implement network usage policy alerting for security and compliance. This is a upgrade on the previous version and further enhancements are planned in the next LANGuardian version.

The image below shows an example of how an alert is configured. This alert will trigger if any user deletes a file called budget2018.xlsx off the network.

New user credentials from SMB sessions

One of the unique selling points of LANGuardian is its ability to associate network activity with actual usernames. It does this by working out what users are assigned what IP addresses on the network. However, it is possible to logon to the network with one username and then use another username to connect to a Windows file share.

LANGuardian 14.4 can now passively capture what usernames and being used to connect to Windows files shares. This is very useful for reporting on what users are connecting to file shares using administrator accounts. It is also very useful when it comes to compliance standards such as GDPR where you may have to identify sharing of credentials to comply with Identity and Access Management (IAM).

The following image shows an example of domain user association with network file share activity. The user logged onto the workstation that accessed the Profit & Loss file was darragh.delaney

The next image shows an example of the new passive username capture from SMB sessions. The actual user that was used to connect to the file server was darragh.

Windows Services (DCERPC) decoder

New New DCE/RPC, short for “Distributed Computing Environment / Remote Procedure Calls”, is the remote procedure call system developed for the Distributed Computing Environment (DCE). This system allows programmers to write distributed software as if it were all working on the same computer, without having to worry about the underlying network code.

A lot of Windows applications use DCERPC to communicate between clients and servers. Examples of this would be network based printing or some Microsoft Exchange services. Previous versions of LANGuardian were able to detect DCERPC but could not drilldown to see what applications were in use. LANGuardian 14.4 now includes a DCERPC decoder so you can drilldown and see what applications are in use.

The screenshot below shows an example of the drilldown. Here we can see how DCERPC is being used mostly for printing and Exchange on my network.

New full packet capture mechanism

We introduced a full packet capture feature in LANGuardian last year. Customers wanted the ability to capture unprocessed network traffic so that they could take a look at it outside of LANGuardian. The first version only allowed you to take packet captures off local network interface cards.

LANGuardian 14.4 now allows you to save PCAPs from any LANGuardian sensor on your network from a centralized GUI. Leverage your LANGuardian installation to get complete coverage for troubleshooting or forensics. The image below shows the packet capture option in use. Clicking on the network interface dropdown now allows you to select any sensor.

Improved accuracy of Google QUIC fingerprinting

QUIC (Quick UDP Internet Connections, pronounced quick) is a transport layer network protocol designed by Jim Roskind at Google. The most common use of QUIC today is for streaming YouTube videos. If you use a Chrome browser then data associated with your YouTube activity uses the QUIC protocol.

LANGuardian 14.4 includes improved detection capabilities for this protocol. The screenshot below shows a typical drilldown. Majority of traffic will be associated with YouTube but you will see QUIC associated with other Google services.

New PDF format option for scheduled reports

Automated email reports are popular with our customers. Many will choose to get reports like Top Network Events, Top Users or Top Applications delivered to their mailboxes every day. For some time these reports were delivered in HTML format. LANGuardian 14.4 now includes a new option where you can get your reports delivered as PDF attachments.

Video: A quick tour of the new features in LANGuardian 14.4

You can download a 30 day trial of LANGuardian from here.

New Devices = New Year Challenges

As 2017 draws to a close I would like to take this opportunity to wish all my business and Infosec contacts a Happy Christmas and best wishes for the new year. It is also the season for exchanging gifts and the top of many peoples list is a new phone, tablet or some other IoT gadget. It is amazing what you can get for so little now. I just watched a video about an Android powered smartwatch that comes with a SIM slot, camera, touchscreen, access to Play Store plus many other features and you get all this for $12.

The challenge that these devices brings is that they may end up on corporate networks. No big deal you may say but all it takes is for one compromised system to bring down your network with a malware infection. The portability is the problem, users walk past your firewall with their shiny new device and suddenly you have a problem inside your network.

Another issue is the potential bandwith grab that new devices bring. Many will need updates and as soon as they get on a network with lots of bandwidth they start downloading updates. Some of these can be over 2GB in size which can swamp WAN or Internet connections.

How can you detect new devices on your network?

One of the best ways to detect new devices on your network is to monitor network traffic going to and from a number of key points including:

1. Internet gateway
2. Internal interfaces of proxy servers
3. DHCP queries
4. DNS queries
5. Network interfaces going to WAN routers

One of the easiest ways to monitor network traffic is to use a SPAN, mirror port or TAP. These allow you to get a full copy of network traffic as it passes through a switch. The main thing to remember is that you don’t need to monitor every port on your network, just focus on the ones I have listed above.

Once you have a traffic source in place you then need to extract certain information from the network packets which will allow you to report on new network devices. For the purposes of this blog I am going to use our own LANGuardian system and it can extract device metadata from the packets. The video below details the steps neccessary to monitor Internet traffic and you can extend this to include other network points.

Monitoring Internet Traffic. Proxy & Direct

One of the richest sources of data when it comes to monitoring new devices is Internet traffic. Most wired and wireless devices try an access external services to download updates or to send and receive data to cloud services. Buried within this data will be certain pieces of metadata which can reveal what devices are on your network.

The image below shows an example of metadata captured from Internet traffic which is then used to build up an inventory of what devices are connecting to your network.

Monitoring DHCP Requests

New devices connecting to your network will normally send out a DHCP request so that it can get an IP address which it then uses to communicate. If you monitor these DHCP requests you can start to build up an inventory of what devices are connecting to your network. The screen shot below shows an example of what you should be capturing. Here you can see the device MAC addresses with associated hostname and IP address. An alert can be triggered on LANGuardian if the MAC address is new so you know when a new device connects to your network.

Monitoring DNS Queries

Once you start to build an inventory of what is connecting to your network, you should also try and capture some associated data. A good example would be to capture all DNS queries that devices on your network are sending. These queries can reveal a lot about what the devices are doing and what sort of applications they are running. In the example below we can see that there is a device active on our network and it is running cloud apps like WhatsApp and GMail and it is running the Township game.

Monitoring network interfaces going to WAN routers

As I mentioned previously, wireless\IoT devices can consume large volumes of bandwidth. Businesses can be impacted if users in remote sites start complaining that the “network is slow” and all it takes is for one device update to swamp a link. Make sure you are monitoring what applications are using your bandwidth.

An easy way to do this is to monitor the network interfaces on your WAN routers with a product like LANGuardian. It can also associated network activity with usernames so you know who is doing what on your network. A sample of this username integration is shown in the image below.

Why worry about VPN clients?

VPNs have been around for a long time. A VPN extends a private network across a public network, and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network. Applications running across the VPN may therefore benefit from the functionality, security, and management of the private network.

If you use public WiFi networks such as those found in airports and cafes then it is recommended that you use a VPN service. A VPN will ensure that all of your communication is encrypted.

Common uses for VPN clients

Good

1. Site to site connectivity where a branch office can connect to HQ via the Internet
2. Allows remote workers to connect to HQ
3. Encrypts your data when you are on a public WiFi network

Bad

1. Bypass web filters (some may not see this as bad)
2. Allows you to run applications which are blocked
3. Create a hole in a Firewall which may become the source of a Malware infection
4. Can be used for data exfiltration

How to detect VPN clients on your network

VPN clients can be difficult to detect as they typically use a port such as 443 over UDP or TCP which is normally open on a firewall. However, there are a number of things to watch out for. First we need to understand how the most common VPN clients work.

Most VPN clients come as a software pack which include the actual VPN software and a database of VPN servers. The idea is that everything you need is included when you install so you don’t need to access a specifc website to connect to anything. If you did it would be easy to block access to these websites. This makes it hard to detect VPN clients if you are looking at reports from something like a web filter.

Once you select a VPN server, an encrypted connection is created between your client and the VPN server. All of your Internet bound activity is then routed through this VPN connection. If you want to browse a website for example, the VPN server connects to the website and sends the text\images\media back to you via your encrypted connection. This is what makes them secure, someone ‘sniffing’ your local traffic can’t see what you are accessing.

In summary, a VPN client makes a direct connection to a VPN server and this server then does the job of accessing what service\application your requested. This differs from users connecting to websites or applications directly. For example I may go and visit YouTube using a web browser. When I type in YouTube.com my computer will go and resolve this name to an IP address using DNS. Computers use IP addresses to connect, not human readable names.

What you need to watch out for is any sessions to external IP addresses which have no hostnames associated with the server. If the connection is over TCP or UDP port 443 then you are probably looking at VPN client activity. The image below shows an example of what to watch out for if you want to detect VPN clients. The first client listed is connecting directly to an IP address as no hostname is shown. The other connections are to Googlevideo which are part of the YouTube service.

Check out the video below to learn more about how you can use our LANGuardian product to detect VPN clients.

Along comes another one. Scarab Ransomware

Scarab Ransomware is just another in a series of Ransomware variants that appeared in 2017. It falls into the crypto Ransomware category which typically go after user data on hard drives and network shares and encrypts it. Scarab Ransomware has the typical three stage infection process:

1. Get a user to click on a link or open an attachment infected with Malware
2. Connect to external websites to download the actual Ransomware
3. Encrypt the users data and leave a ransom note

The name Scarab is also associated with a family of beetles. Scarabs are stout-bodied beetles, many with bright metallic colours, measuring between 1.5 and 160 mm. They are also known as a dung beetle.

Detecting the presence of Scarab Ransomware

First spotted on November 23, the Scarab ransomware is being sent primarily to .com addresses, followed by co.uk inboxes. It was sent to millions of email addresses in the first four hours alone, according to Forcepoint. The emails are originating from hosts within the Necurs Botnet.

The unsolicited emails in question come with the well-worn “Scanned from {printer company name}” subject line and contain a 7zip attachment with a VBScript downloader. Use SMTP traffic monitoring or check the logs on your email server for any subject lines which start with “Scanned from”.

Another key indicator of Scarab Ransomware is the presence of these types of files on network shares:

• Files with the extension “.[suupport@protonmail.com].scarab”
• Ransom notes which are saved as text files with the name “IF YOU WANT TO GET ALL YOUR FILES BACK, PLEASE READ THIS.TXT”

The image below shows how our LANGuardian product detected suspicious activity on a network share by monitoring network traffic going to and from the file servers. When you monitor network traffic like this you can passively generate a list of all file and folder activity without the need for logging or agents.

Watch out for an increase in file renames. A sure sign of Scarab Ransomware activity

File renames are not a common action when it comes to activity on network file shares. Over the course of a normal day, you may end up with just a handful of renames even if you have hundreds of users on your network. When Scarab Ransomware strikes, it will result in a massive increase in file renames as your data gets encrypted.

You can use this behavior to trigger an alert. If the number of renames go above a certain threshold, then you have a potential Ransomware issue. Our recommendation is to base your alert on 4 or more renames per second.

The video below shows how you can setup a LANGuardian trend graph which you can then use to create an alert. It also demonstrates how you can setup a file activity monitoring report which shows any filenames with extensions known to be associated with Ransomware. You just need to change the file extensions to the ones mentioned earlier in this blog post.

What are SYN packets?

Last week I was on the road in Scotland visiting some of our university customers. During a meeting with a Network Security Specialist, a network issue popped up and he said to me “our firewall is triggering SYN packet alerts, is there anything you can do to help?”

SYN packets are normally generated when a client attempts to start a TCP connection to a server, the client and server exchange a series of messages which normally runs like this:

1. The client requests a connection by sending a SYN (synchronize) message to the server.
2. The server acknowledges this request by sending SYN-ACK back to the client.
3. The client responds with an ACK, and the connection is established.

This is called the TCP three-way handshake, and is the foundation for every connection established using the TCP protocol. In the past attackers could bring down a firewall by sending lots of SYN packets. Each SYN packet would use up firewall resources and eventually it would stop accepting new connections. This can result in a massive business problem now that so many applications are cloud based and need fast and reliable Internet access.

A SYN alert could be the sign of attacker reconnaissance

Modern firewalls are able to deal with SYN attacks better by limiting the rate of SYN requests amoungst other things. However, they still retain their alerting features so if something usual is spotted they will trigger an alarm.

Not all SYN alerts are attacks designed to bring down your firewall. This was the case with the customer I mentioned earlier. In summary they were getting a lot of connections from a host in China which was trying to find any systems running SSH services. This is very common, attackers often seek out SSH servers, once found they try and do a dictionary attack against the root or other accounts. If they are successful then they have full access to the LAN segment that the SSH server sits on.

The image below shows a sample of the events from our LANGuardian system. Each one of these is triggered when a host tries to connect to more than 300 other systems in 25 seconds or less. At the same time the firewall on the same network was triggering excessive SYN packets alerts. The fix in this case was to get the ISP to block the Chinese host.

How to get visibility at the network edge

If you want to see what is hitting your firewall then you need to monitor network traffic hitting the outside network interfaces. Typically this is done by setting up a SPAN or mirror port on the network switch which connects to the external interfaces.

The image below shows a typical setup. Network packets destined for the LAN or DMZ are analyzied by a traffic analysis tool connnected to the network switch which connects devices together outside the LAN firewall. Most servers located here will have a public IP address and so would be open to network scanning activity. You can also detect SYN packet rates at this point, see what is hitting your main firewall.

One of the main things I watch out for in the DMZ is the rate of connection attempts. This is similar to detecting SYN attacks but as I mentioned, most of this activity is associated with reconnaissance, attackers trying to find a backdoor into your network. Some of the firewalls I looked at will trigger SYN attack alerts when they start received around 10,000 connection attempts per second but this can vary.

The image below is from one of our LANGuardian systems. It is reporting the level of what we call netscans, a netscan is triggered when one host tries to connect to more than 300 others in less than 25 seconds. An alert is triggered when this goes over 20 events per second. Our testing has shown that some firewalls start triggering their own alerts when this rate is reached and may start dropping  or refusing connections.

We have seen instances, for example DDOS attacks, where the organisation’s firewall is under some much pressure trying to handle the attack, it cannot be accessed and used as a reporting or forensics tool. Another advantage of using a continuous but passive system such as the LANGuardian, it can always be accessed when required and as it is not inline, can never have any impact on network availability or performance.

The video below goes through the steps needed to setup a SPAN or mirror port to monitor network traffic. The example covered looks at monitoring the internal LAN interfaces of a firewall but you can apply a similar approach when it comes to monitoring the external interfaces.

Using Traffic Analysis as a Data Source

As we have mentioned numerous times in our blogs, Network Traffic Analysis or (DPI) Deep Packet Inspection is a very flexible technology. It can be used for many use cases including continuous monitoring of user and device activity, reporting, forensics, analytics and of course troubleshooting of everyday  problems. One of the benefits of using a DPI engine to analyse network traffic flows, is the rich application specific detail and context, metadata that can be extracted and presented in real time or stored for forensics. Data ideal for many IT security and operational use cases.

DPI can sometimes be seen as a ‘complex and expensive technology’ only suitable for large enterprise, but not with the latest engines as found in the NetFort LANGuardian. The basic principle of the LANGuardian engine is to get the engine to do all the ‘heavy lifting’, reassembly, analysis, alerting thus making it very easy to use and read, ideal for all skill levels across organisations of all sizes with minimum training.

Actionable Alerts That Our Customers Requested

Recently we have been asked by our customers to generate real time alerts on various network and user activities that are critical to them. Examples, in the customers own words include:

• US Manufacturing company
  • ‘Alert if a user or device generates more than x GB of data over a given time?’
  • ‘Alert if certain file types are detected (e.g. mkv files)? ‘
• Large EU University
  • ‘Alert when a machine on our network is maliciously scanning 100,000’s of IP addresses across
    the globe. ‘
• EU Online retail company
  • ‘Any internal ip address making a connection to an external ip where the connection (TCP/UDP) was not preceded by a DNS query that returned the external ip’
• EU Government organisation
  • ‘Alert on any web accesses not via the proxy server’
• US City Council
  • ‘I’m trying to figure out the syntax for a rule to detect when the BitTorrent protocol is detected’
  • Oct 2016 ‘ Detect SMB1 traffic Is there a way to detect SMB1 traffic? Microsoft recommends to stop using it so I’d like to see if it’s being used in our network.’
• US Law firm
  • ‘Alert if a lawyer uploads huge files to our shared server within a short period of time using up all our space’

Some seem very obvious, simple but on closer examination, most make sense. Also, it is interesting to note that most customers do not request that many, maybe because they are already flooded with false positives and find it almost impossible to actually spot the real actionable alerts.

Machine Learning

I had a chat with a customer last week who purchased a pretty well known ‘machine learning’  based network security products 6 months ago, when he mentioned the product name, I was very curious and asked how it was going. ‘Nothing yet, 6 months of false positives, but you know, it is still learning’. So now not alone have they invested a lot of time and money in purchasing and implementing a product but it is also costing them time wise every day, as it giving them even more false positives to investigate!

Actually, a small number of our customers who requested the alerts included in the list above have recently implemented some expensive ‘Machine learning’ based security products. We started discussing it here internally and it got us wondering about the massive hype by vendors, analysts etc, around machine learning with respect to security. What is really driving it ? The lack of skilled security analysts is definitely one factor, big data another, but another one is surely the current set of overly complex and expensive security products ? And maybe he venture capitalists who have invested huge amounts of money in companies developing this technology, many of whom are struggling with sales ?

Developing Our Own Alerting Engine

We are putting huge focus on the usability of our alert engine, make sure it is as easy as possible to define the rules that generate real actionable alerts, not false positives, the alerts important to the user, the organisation, the business.

Of course, sometimes the simple and best ones are not that easy to implement. For example, as in the case of a lack of a DNS query require context/state and some understanding of the protocol in use in order to generate an alert. As mentioned by one of our engineers, some are also somewhat vague and require more detail. It may also be that some do not require an instant alerts, a simple email sent to the administrator each morning may suffice.

It will take time to get right, some tuning, knowledge of the network etc. Ease of use, readable data, is a must otherwise it will never work. These are basics some security vendors simply do not pay enough attention to but instead spend a lot of time and money on graphics and web interfaces designed by gamers, dark constellations which look fantastic but when you start to look at the detail, looking for actionable intelligence, you start thinking what is this really telling me ?

There are many common and critical threats or ‘bad’ network and user activities that do not require sophisticated artificial intelligence or machine learning.  Most organisations do not have the resources to monitor various dashboards to actually try and detect suspicious activity in real time,  but simply want a real alert with some readable context and data to understand what the alert is actually telling them.

Where to Start

Is it not common sense, start small, work the basics. Use a network traffic analysis for example to monitor internal activity and get the visibility you need to understand what is happening on your network. Modify your ‘active’ systems for example your firewall, to get rid of everything that could widen your attack surface and then add alerts, one by one, to ensure you are immediately notified the next time.  Use forums, blogs, your own network to keep in touch and build and update your own alert set. Add them one by one, you will be amazed with the size of your list after a few months and the lack of false positives.

Network Zombies

Now that Halloween is behind us we can put away the scary decorations and funny costumes. It may also be a good time to check our networks for zombie hosts or users. They can take many forms

1. Clients infected with Malware which form part of an external botnet
2. Faulty equipment which may be generating excessive broadcast traffic
3. Rouge IoT devices eating bandwidth
4. External clients scanning your network perimeter and exploiting firewall holes
5. Misuse of network resources by one or more users

Infected Clients

Many networks have lots of security devices at the network edge. From Firewalls to IPS type systems, securing the perimeter has been a priority for many IT managers. The trouble is that while this is a good thing to do, malware can still get in and unless you are monitoring what is going on inside your network you may be at risk. A user may bring in a USB stick laden with Malware for example and walk past your firewall.

I recently read about this network breach where unauthorized software was found on a server and it may have led to data loss. Some time ago I installed a trial version of our LANGuardian product onto a network and we found a client sending over 10,000 SPAM emails per hour. The interesting thing here was that the user of the computer was not complaining and an antivirus scan did not find anything. In the end the IT manager had to get the system reinstalled.

One way to find out what is happening on your internal network is to monitor network traffic moving through your core switch by setting up a SPAN or mirror port. Network traffic is an excellent source of user and application information. Once you have your data source in place a combination of network based intrusion detection and metadata analysis will root out any suspicious activity.

The image below taken from our own LANGuardian system shows an example of what to look out for. Events such as ET MALWARE Win32/InstallCore Initial Install Activity 1 or ET TROJAN W32/WannaCry.Ransomware Killswitch Domain HTTP Request 1 need to be investigated and the associated clients need to be removed from the network.

Faulty Network Equipment

Technology can be wonderful when it works but when something goes bad it can be a nightmare to figure out what went wrong. A few years back there was massive disruption to air traffic at Dublin airport when a network card went faulty and caused the breakdown of a radar system. Our support team here worked with one of our own customers a while back when a faulty IP phone brought down an entire network segment by sending out large volumes of broadcast traffic.

Make sure you have some sort of internal traffic monitoring in place and watch out for what systems are sending large volumes of broadcast or multicast traffic. In other cases you may need to look at switch interface counters such as collisions or CRC rates. The image below is from our LANGuardian product and show a sample report which is the top clients associated with broadcast traffic. Any devices associated with hundreds of megabytes of broadcast traffic would need to be investigated.

Rogue IoT devices

Almost everything in today’s world is connected. From light bulbs to fridges, many devices now want to share data and metrics. However, this IoT world is not without its challenges. Recently security researches uncovered a botnet called Reaper which may have infected over 1 million networks.

IoT Botnets are Internet connected smart devices which have been infected by the same malware and are controlled by a threat actor from a remote location. They have been behind some of the most damaging cyberattacks against organizations worldwide, including hospitals, national transport links, communication companies and political movements.

You need to be aware of what is connecting to your network. One way to do this is to monitor all traffic going to and from your DHCP and DNS servers. This can reveal a lot about what is connecting to your network and what they are trying to get to. The images below from our LANGuardian product show how metadata captured from DHCP and DNS traffic can used to get an inventory of what is on your network.

If you do have IoT devices on your network, you need to make sure they are fully patched and not using any default passwords.

External Clients Targeting Your Network

As I mentioned previously there are large botnets out there ready to target unsuspecting businesses and organizations. If you re unlucky enough to be targeted you could be on the receiving end of large DDoS attack. Typically NTP or DNS traffic is used to overload your Internet gateways resulting in a loss of connectivity for internal and external clients. Make sure you are monitoring all traffic at your network edge especially the levels of UDP based protocols such as NTP or DNS.

Also watch out for any external clients scanning your network looking for open ports on firewalls. Common scans would be on RDP (TCP 3389), SSH (TCP 22) or SQL (1433). You need to take action if you see any connections on your internal network from clients which are outside the network. Either block the external IP address or shutdown the port they are using on your firewall. Don’t forget to carry out a forensic investigation on any incidents and see if any other client was targeted inside your network.

The image below from our LANGuardian product shows and example of what to watch out for. Here we can see an external IP which is registered in Russia connecting to servers on the local network over TCP port 445.

Rogue Network Users

Sometimes a network user can go bad. Maybe they install an application such as Bittorrent and hog all of the Internet bandwidth or maybe someone accidentally or deliberately deletes data. Can you track down all activity by username? One way to do this is to capture user logon information from Active Directory and use this to match it to IP addresses so you can see who is doing what.

The image below from our LANGuardian product shows a sample user report which lists the top users active on the network based on data downloaded or uploaded. You may want to consider getting alerts if users go above certain levels.

What is Badrabbit Ransomware?

A new strain of ransomware nicknamed “Bad Rabbit” has been found spreading in Russia, Ukraine and Germany. The outbreak bears similarities to the WannaCry and Petya ransomware outbreaks that spread around the world causing widespread disruption earlier this year. This Ransomware encrypts data on infected machines or on network file shares before demanding a payment of 0.05 bitcoin (£250) for the decryption key.

They main way Bad Rabbit spreads has been identified as drive-by downloads on hacked websites. No exploits are used, rather visitors to compromised websites – some of which have been compromised since June – are told that they need to install a Flash update. Of course, this is no Flash update, but a dropper for the malicious install.

Once a user facilitates the initial infection the malware leverages existing methods to propagate around a network without user interaction. This involves leveraging an exploit in the SMB protocol and a hacking tool known as Mimikatz, which is able to obtain passwords from memory on the infected system,

Checking your IDS

An intrusion detection system (IDS) is a device or software application that monitors a network or systems for malicious activity or policy violations. Most look for certain data strings within network packets which will then trigger an alert. In the case of Badrabbit you need to be watching out for the following emerging treats rules.

• emerging-trojan ET TROJAN BadRabbit Ransomware Activity Via WebDAV (cscc)
• emerging-trojan ET TROJAN BadRabbit Ransomware Activity Via WebDAV (infpub)
• emerging-trojan ET TROJAN BadRabbit Ransomware Payment Onion Domain

If you are using our LANGuardian product, check the report Top Network Events. This is also available in the trial version.

Suspicious Domains

Badrabbit uses a number of domains for command and control services. Check your DNS traffic and/or your web activity logs for any activity associated with these domains. If you detect any activity, remove the client which issued the DNS query or tried to access the domain from your network.

1dnscontrol.com
an-crimea.ru
ankerch-crimea.ru
argumenti.ru
fastmonitor1.net
caforssztxqzf2nm.onion

If you are using our LANGuardian product, check the report Network Events (DNS Lookups). This is also available in the trial version.

Watch out for an increase in file renames.

File renames are not a common action when it comes to activity on network file shares. Over the course of a normal day, you may end up with just a handful of renames even if you have hundreds of users on your network. When Ransomware like Badrabbit strikes, it will result in a massive increase in file renames as your data gets encrypted. Note that Badrabbit will use the same file names so there are no file extensions to watch out for.

You can use this behavior to trigger an alert. If the number of renames go above a certain threshold, then you have a potential Ransomware issue. Our recommendation is to base your alert on 4 or more renames per second.

The video below shows how you can setup a LANGuardian trend graph which you can then use to create an alert. It also demonstrates how you can setup a file activity monitoring report which shows any filenames with extensions known to be associated with Ransomware.

What is Magniber Ransomware?

Magniber Ransomware was first discovered by security researcher Michael Gillespie. It is a crypto ransomware, which aims to encrypt personal data and files. At the moment it is only targeting users in South Korea and the Asia-Pacific regions. The Ransomware is primarily being distributed by the Magnitude exploit kit, a primary distribution vehicle in the past for Cerber Ransomware.

Monitoring File Activity on Your Network

You need to be monitoring file and folder activity before you can detect any variant of Ransomware on your network. One of the easiest ways to do this is to monitor the network traffic going to and from your network file servers. Most managed switches support SPAN or mirror ports and these allow you to get a copy of the network packets going to and from your file servers.

Once you have your data source in place you can use a tool like our own LANGuardian to extract file and folder metadata from the network packets. Metadata includes things like filenames, actions and usernames. As well as monitoring traffic associated with your file servers we also recommend that you monitor all traffic at your network perimeter. Ransomware needs to communicate with the outside world so having visibility at the network edge is important when it comes to detecting and alerting on Ransomware activity.

How to detect the presence of Magniber Ransomware

1. Watch for any files with .ihsdj & .kgpvwnr  extensions
2. Ransom notes associated with Magniber will contain the text READ_ME_FOR_DECRYPT
3. An increase in file renames is a sure sign of Ransomware.
4. Check for the presence of any TOR clients on your network

.ihsdj and .kgpvwnr  file extensions

Magniber Ransomware targets certain file extensions. When it encounters a targeted file type, it will encrypt the file and append the extension .ihsdj or .kgpvwnr to the to the encrypted file’s name. Watch out for any files with extensions like these on network file shares. If you spot any you need to take the client that created them off the network.

The image below shows an example of what to look out for. It was generated by using the LANGuardian Windows File Shares :: Filenames by Actions report to focus on any files with the extension .ihsdj or .kgpvwnr

Ransom note filename will contain the text READ_ME_FOR_DECRYPT

While encrypting your data, Magniber will create a ransom note named READ_ME_FOR_DECRYPT_[id].txt in each folder that a file is encrypted. The ID will be unique to you. Any clients creating these text files need to be removed from your network and blocked permanently or reinstalled.

The image below shows an example of what to look out for. It was generated by using the LANGuardian Windows File Shares :: Filenames by Actions report to focus on any files with this text string in the name.

Watch out for an increase in file renames. A sure sign of Ransomware activity

File renames are not a common action when it comes to activity on network file shares. Over the course of a normal day, you may end up with just a handful of renames even if you have hundreds of users on your network. When Ransomware strikes, it will result in a massive increase in file renames as your data gets encrypted.

You can use this behavior to trigger an alert. If the number of renames go above a certain threshold, then you have a potential Ransomware issue. Our recommendation is to base your alert on 4 or more renames per second.

The video below shows how you can setup a LANGuardian trend graph which you can then use to create an alert. It also demonstrates how you can setup a file activity monitoring report which shows any filenames with extensions known to be associated with Ransomware.

Watch out for TOR clients on your network

Tor is free software for enabling anonymous communication. The name is derived from an acronym for the original software project name “The Onion Router”. Tor directs Internet traffic through a free, worldwide, volunteer overlay network consisting of more than seven thousand relays to conceal a user’s location and usage from anyone conducting network surveillance or traffic analysis.

Magniber Ransomware uses TOR based payment systems called My Decryptor that is located at the TOR url [victim_id].ofotqrmsrdc6c3rz.onion. This site will provide information on the ransom amount, the bitcoin address payments must be made, and information on how to purchase bitcoins.

As IDS system can detect the presence of TOR clients on your network. While a TOR client is not an indication of Ransomware activity, you should look at removing them from your network or find out why users need to use such a service. The image below shows an example of what to watch out for.

What is the QUIC Protocol?

QUIC (Quick UDP Internet Connections, pronounced quick) is a transport layer network protocol designed by Jim Roskind at Google. QUIC supports a set of multiplexed connections between two endpoints over User Datagram Protocol (UDP), and was designed to provide security protection equivalent to TLS/SSL, along with reduced connection and transport latency, and bandwidth estimation in each direction to avoid congestion. QUIC aims to be nearly equivalent to an independent TCP connection, but with much reduced latency.

The most common use of QUIC today is for streaming YouTube videos. If you use a Chrome browser then data associated with your YouTube activity uses the QUIC protocol. Some reports suggest that QUIC now accounts for more than 5% of Internet Traffic. Other browsers such as Opera version 16 and above also support the QUIC protocol but don’t have it enabled by default.

How to detect QUIC protocol use on your network

The most reliable way to detect QUIC protocol use on your network is to monitor network traffic at your network edge. Our LANGuardian product can use this data source to look at packet payloads and identify what protocols are in use. The video below shows how to set up a SPAN or mirror port to capture traffic at your network edge.

Once you have your LANGuardian in place you need to click on Reports \ Top Protocols. In my case the QUIC protocol account for 78% of bandwidth use.

Drilling down on this we can then see the Googlevideo domain and the usernames associated with this activity. Googlevideo is the domain Google use for streaming YouTube content.

Upgrade your LANGuardian to enable QUIC detection

QUIC detection was added to LANGuardian version 14.3.2. If you are a customer you must upgrade to this or higher version. Click on the gear symbol top right, then settings \ LANGuardian software upgrade. Your LANGuardian must have Internet access to check for and download the latest version.

If you are not a LANGuardian customer then you can download a 30 day trial and see within minutes how much bandwidth the QUIC protocol is using on your network.

What is BitTorrent Traffic?

BitTorrent is a communication protocol for peer-to-peer file sharing (“P2P”) which is used to distribute data and electronic files over the Internet. It is most famous as a method for downloading copyrighted material such as movies and music. However, it can be used for software delivery and Microsoft have some P2P capabilities built into Windows 10 for distributing Windows updates.

When it comes to monitoring BitTorrent traffic you need to understand how the protocol works. It is not like a traditional download, where you download everything from a single link or IP address. Instead, you download pieces from other clients (peers) and the management is looked after by trackers or more commonly Distributed Hash Tables. Every download has an associated INFO-HASH value which is unique to it and this is an important piece of data when it comes to identifying BitTorrent traffic.

Capturing BitTorrent Traffic

There are multiple potential data sources if you want to monitor BitTorrent traffic on your network.

• Monitor network traffic at your network edge using a SPAN, mirror port or TAP
• Flow records such as NetFlow or IPFIX
• Firewall logs

The most reliable source is network traffic as “packets don’t lie”. Flow records will not capture metadata such as INFO-HASH values, so you will never know for definite that traffic is associated with BitTorrent activity. Firewall logs may indicate the presence of BitTorrent, but they are not designed as a forensics tool to store long-term records of all traffic and application information.

The video below shows how to set up a SPAN or mirror port to capture traffic at your network edge. With a tool like LANGuardian connected to this, you can identify BitTorrent traffic and capture important metadata such as INFO-HASH, IP addresses, external clients and file names.

Analyzing BitTorrent Traffic

When it comes to analyzing BitTorrent traffic you need to be watching out for these applications:

• BitTorrent DHT Tracker
• BitTorrent Peer Traffic

Once you detect these applications on your network, you need to capture certain metadata so you don’t need to store every packet which can be expensive. The image below shows the output of a LANGuardian BitTorrent analysis report. Note how you can see the network user, IP address, INFO-HASH and file name.

If the download is associated with a private tracker you may not see any filenames. In that case you should look at the destination IP addresses as they can reveal a lot about the applications associated with the Bittorrent traffic. In the image below we can see that there is some Bittorrent activity associated with a client and looking at the destination IP addresses it would appear that the user has the uTorrent application installed.

Tracking BitTorrent Traffic on Your Network

Download a free trial of LANGuardian today, if you would like to check for any BitTorrent activity on your network. It comes with a fully featured BitTorrent reporting engine together with Active Directory integration, so you can associate network activity with usernames.

Integrating LANGuardian with Active Directory allows you to search network activity by user name as well as IP address. It is ideal for environments where DHCP is used. You need to complete these five steps to enable the integration.

1. Create an AD account which your LANGuardian will use for logging onto domain
2. Assign WMI permissions to this user
3. Add user to Performance Log Users  and Event Log Readers groups
4. Check access rights using wbemtest application
5. Configure AD integration on LANGuardian

1. Create a standard user logon for LANGuardian

You can use an existing account for AD integration, but for the purposes of this guide, we are going to create a new one called LANGuardian. This account does not need to be an administrator or in the domain admins group but it does need extra permissions which are described below.

We recommend that the account is set with a password which does not expire as there is no facility within the LANGuardian GUI to set AD passwords.

2. Assign WMI permissions

You need to logon to each domain controller and grant specific WMI permissions to the new user.

Click on start\run and type in wmimgmt.msc. In the WMI Management window, right click on the WMI Control sub menu and select Properties. Under Security Tab select CIMV2 and click on the Security button in the bottom right corner.

Add the LANGuardian AD account and verify that Enable Account, Remote Enable and Read Security is Allowed, if not, enable those permissions and apply your settings.

3. Add user to Performance Log Users  and Event Log Readers groups

Use the Active Directory Users and Computers application to add the LANGuardian AD account to the groups Performance Log Users and Event Log Readers.

4. Check configuration and permission using the wbemtest application

Test the WMI configuration and permissions using the native Windows tool WBEMTEST from your desktop

1. Click on run and type in wbemtest on a Windows 7 or 10 system
2. Click on connect and type in \\x.x.x.x\root\cimv2 into the namespace field where x.x.x.x is the IP address of a domain controller
3. Use the LANGuardian AD account with password and click on connect
4. If the account has permissions to connect via WMI you should not see any error messages

If the steps above fail add the LANGuardian user account to the domain group Performance Log Users and try running the test again. If this fails then try the test using the Administrator account to see if the server is blocking all remote WMI connections.

Optionally click on Query and type in:

This command verifies that the account can run a query and see the user logon events. If you do not get any data back from the query you may not be auditing user logon events or the LANGuardian AD account is not in the Event Log Readers group.

5. Configure AD integration on LANGuardian

Logon to the LANGuardian GUI and click on the gear symbol top left then settings \ Identity \ Active Directory. Click on add domain and enter the IP address of one domain controller together with the LANGuardian AD account.

Video Guide: How to setup Active Directory integration using WMI

Gryphon Ransomware

Gryphon Ransomware is actually a variant of the BTCWare ransomware. This family of Ransomware typically uses RDP (remote desktop protocol) brute force attacks to spread within computer networks. Once the hacker gains access to a computer, they will install the ransomware and encrypt the victim’s files.

What you need to watch out for

1. Inbound RDP connections

RDP can be a useful IT tool for managing user systems remotely. However, it is not a protocol that you should leave open at your network edge. Watch out for inbound RDP connections from external clients. RDP typically uses TCP port 3389 for connections. The screen shot below shows an example of what you should be capturing with your network traffic monitoring tool. In my case, the connections are local to my LAN.

2. Increase in file renames on network shares

When Ransomware strikes it often seeks out network file shares as that is where the most valuable data is. One way to detect if Ransomware has become active on your network is to monitor the rate of file renames. When Ransomware encrypts data it renames files with a new extension.

File rename rates can be captured by monitoring the network traffic going to and from your network file servers. A tool such as our own LANGuardian can then use this data source to create an audit trail of file and folder activity.

The image below is an example of what you should be watching out for. The graph shows an increase in file renames and the client responsible for this is also shown. An alert can also be triggered when this activity is detected.

3. Crypton file extensions

When Gryphon Ransomware strikes a network it appends the .Crypton extension to encrypted files. Any client that is renaming files with this extension, need to be taken off the network immediately. The image below shows an example of what you should be watching out for; in this example, a database file was renamed with the .Crypton file extension.

Worried about Ransomware? Download a free trial of LANGuardian today

If you want to audit your network for signs of Ransomware activity; download a 30-day free trial of LANGuardian here. This includes a pre-configured Ransomware dashboard, so you get instant visibility of any suspicious activity.

Why monitor network traffic?

The recent Equifax security breach resulted in hackers getting their hands on the sensitive personal information of 143 million American consumers. The breach lasted from mid-May 2017 through July 2017. The hackers accessed people’s names, social security numbers, birth dates, addresses and, in some instances, driver’s license numbers. They also stole credit card numbers from about 209,000 people and dispute documents with personal identifying information from about 182,000 people; they also grabbed personal information of people in the UK and Canada.

This information was not carried in briefcases. It left the organization as a payload in network traffic, mixed in with the massive amounts of legitimate traffic that would have left Equifax during the hacking period. While it is good practice to have firewalls and threat detection systems, many of them rely on known signatures of exploit attempts. This approach fails if you are targeted with something new, or if your security applications are missing detection capabilities for a specific type of attack. This is one of the main reasons why you need to constantly monitor network traffic leaving and entering your network.

What is a CCTV system for monitoring network traffic?

When I talk about a CCTV type system for monitoring network traffic, I usually give this analogy. When we want to protect physical buildings, we invest in locks, gates, walls and other physical barriers to protect our property and physical assets.

Too often in the digital world, we forget about monitoring tools. Senior management often sees them as a ‘nice to have’ as there is no obvious payback. It is easy to get seduced into spending IT budgets on fancy firewalls and threat prevention systems as they can take an action. However, the Equifax hack has reminded us that we need eyes on our networks 24/7 and we need to keep historical records of who is connecting to what so that we can go back and see how someone hacked into our network.

A CCTV system for network traffic can be based on flow or packet analysis. If you use managed switches or if you have a router, you will have a data source. From this analysis, you need to be capturing information such as:

• True application names as you cannot rely on port labels
• Resource (URI) names
• HTTP header fields
• Web client information
• DHCP data such as IP addresses, MAC and host-names
• SMTP metadata such as email addresses and subject lines
• BitTorrent Hash values
• DNS SPAM detection
• SMB and NFS metadata
• Ingress and egress IP flows including IP addresses and port numbers
• Associated GeoIP details
• Packets counts
• IP flow counts
• Detect application layer attacks
• Associated usernames
• Accurate web domain names from DNS, HTTP or HTTPS traffic analysis

One of the most important things is that you get both a real-time and historical view of this data. Most network monitoring applications do real-time monitoring. Some do historical reporting but may age and compress data to cut down on disk usage. This is not ideal, as you will want to store as much detail as possible so that you can investigate historical events. Make sure you choose a forensics or monitoring application that retains all information captured.

Integrating IDS (Intrusion Detection System) and traffic analysis are also beneficial. This allows you to detect known attacks as well was providing extra context like what connections were made and if the attackers targeted any other systems on your network. You will only get good threat detection with packet analysis, flow (NetFlow, IPFIX, etc) will struggle as they don’t look at packet payloads.

Your monitoring tool needs to be independent of edge equipment

Many firewalls now come with advanced logging and reporting capabilities. On paper, they tick boxes for both prevention and reporting. However, if your network is under attack you may find that these logs become inaccessible.

Some time ago I attended a JANET conference in the UK. A number of universities had been targeted with DDoS attacks. Many network managers spoke about how they struggled to understand what was happening, as their firewall logs were inaccessible or were filling up so quickly it was difficult to get an overall view of where the DDoS traffic was coming from. One of the recommendations from the conference was to ensure your monitoring tools were independent of edge devices such as firewalls or routers.

Don’t wait for a breach before investing in monitoring tools

The worst way to implement monitoring tools is to do so in the middle of an attack. You will never capture all the information you need and you may be rushed into buying tools that don’t address your requirements. Get something in place ASAP and use the CCTV analogy when discussing with senior management.  In today’s world, you need to be watching over your network 24/7.

Locky Ransomware

Ransomware has been the number one cyber-security threat in 2017. Outbreaks such as WannaCry have caused massive amounts of damage worldwide. If you want to detect Ransomware such as WannaCry you should watch out for an increase in file renames and deploy technologies such as IDS to identify outbreaks on your network.

Recently there has been an increase in activity associated with the Locky variant of Ransomware. Locky was first detected in 2016 and one of its first victims was the Hollywood Presbyterian Medical Center in Los Angeles, California. The infection encrypted systems throughout the medical center, locking staff out of computers and electronic records.

The recent Locky campaign saw 23 million messages containing the ransomware sent on 28 August across the United States in what appears to be one of the largest malware campaigns this year.

5 Locky Fingerprints that you need to watch out for

If you want to detect Locky activity on your network, you need to watch out for this activity. Some are directly associated with Locky, others would be suspicious and would need to be checked.

• Dodgy subject lines which are known to be associated with Locky distribution
• Clients trying to access the domain greatesthits.mygoldmusic.com
• Lukitus file extensions on network drives
• Increase in file renames
• ZIP file attachments

Further information below on each of these.

Search inbound email for specific subject lines

The email campaign associated with the latest outbreak of Locky uses this list of subject lines:

• please print
• documents
• photo
• images
• scans
• pictures

If you host your own email servers, you should monitor all SMTP servers and alert if any emails using these subject lines are detected. One way to do this is to use our own LANGuardian product to extract the email metadata from network traffic which can be sourced from a SPAN or a mirror port. The image below shows an example of what you should be watching out for.

Monitor DNS or Web Traffic for activity associated with Locky domains

This Locky outbreak uses Visual Basic Script (VBS) files embedded in zip email attachments. The emails do not contain the Ransomware code. When a user opens the attachment the VBS script attempts to connect to the domain greatesthits.mygoldmusic.com. From here, it pulls down the Locky Ransomware and then goes about encrypting files. You can check for activity associated with this domain by monitoring web or DNS traffic. It may also be possible to do this with a firewall or proxy logging, but check your device to see if it capture domain names.

The image below shows an example of what you should be watching out for. Here, we can see that a client attempted to access a suspicious domain and would need to be taken off the network and checked.

Watch out for Lukitus file extensions

Once this variant of Locky is active on a network, it will seek out local folders and network based file shares. Files are encrypted and a Lukitus file extension is appended to each file. Make sure you are monitoring all activity to your important network shares. One way to do this is to monitor network traffic to and from the file servers.

The image below shows an example of what you need to watch out for. The client associated with this event would need to be removed from the network and checked for Ransomware infection.

A sudden increase in file renames is a sign of Ransomware

All variants of Ransomware which target end user data have common attributes which are to take the user data, encrypt and then rename with a new file extension. In some cases, the files are encrypted with their original file names but the rename action still occurs.

We recommend that you constantly monitor the rate of file renames on all of your network shares. A good starting point would be to alert on any instances, where the number of file renames goes above 4 per second. Our lab analysis shows that this is a good indicator of mass renaming which is typically associated with Ransomware. Make sure your alerts also contain the client IP address associated with the renaming as they need to be removed from the network immediately.

Get an inventory of what ZIP files are coming into your network

Compressed files (ZIP and others) are often used to deliver malware via email. Many email servers block attachments if they have strange file extensions. However, if the malware is embedded within a ZIP  file, it can get through some filters. Most network devices are able to open ZIP files which is why they are used.

If you host your own email servers, we recommend that you monitor all attachments that are inbound into your network. One way to do this is to monitor network traffic going to and from your email servers. A system such as our own LANGuardian can extract attachment names from this traffic and provide reports and alerts on suspicious activity.

For more information, take a read of this blog post which looks at 5 Methods For Detecting Ransomware Activity. If you need to put monitoring in place today; download a 30 day trial of our LANGuardian product, which includes a Ransomware monitoring dashboard out of the box.

The New York State Department of Financial Services (“DFS”) has been closely monitoring the ever-growing threat posed to information and financial systems by nation-states, terrorist organizations and independent criminal actors. Recently, cybercriminals have sought to exploit technological vulnerabilities to gain access to sensitive electronic data.

23 NYCRR 500: What it means for you

NYCRR 500 is a regulatory compliance standard that regulates the Financial Services Industry (FSI) in New York. This regulation mandates each institution have a cyber security program, Chief Information Security Officer (CISO), access controls, asset management, data governance, software development practices, annual certification of their compliance, and more.

NYCRR 500 requires that banks, insurance companies, and other financial services institutions regulated by DFS to establish and maintain a cybersecurity program designed to protect consumers and ensure the safety and soundness of New York State’s financial services industry.

The key date to keep in mind is September 1, 2017: that date marks the end of the 180 day period to comply with the guidelines set forth in 23 NYCRR 500.

The key elements of the proposal are as follows, and a summary of these elements can be found here:

1. Establishment of a Cybersecurity Program to include:
   • Adoption of a written Cybersecurity Policy
   • Identify and assess internal and external Cybersecurity risks that may threaten the security or integrity of data stored in an organization’s IT systems.
   • Use defensive infrastructure and implementation of policies and procedures to protect the IT systems from unauthorized access or malicious acts.
   • Detect cybersecurity events.
   • Respond to identified or detected Cybersecurity events to mitigate any negative effects.
   • Recover from Cybersecurity Events and restore normal operations and services.
   • Fulfill applicable regulatory reporting requirements.
2. Mandatory Chief Information Security Officer
3. Cybersecurity Training for Employees
4. Third-Party Service Providers Risk
5. Incident Monitoring and Reporting
6. Information Security Audits

How LANGuardian can help with 23 NYCRR 500

While no one system can provide the full range of compliance across all of the regulatory requirements, a forensic threat investigation solution and incident response plan will be the most important tools for demonstrating compliance.

Written policies (as defined in section 500.3) are an important first step, but compliance requires the demonstration of consistent policy enforcement. Forensic data and reporting are needed to demonstrate consistent enforcement of these new rules, and there are four sections in particular where LANGuardian provides many benefits.

Section 500.02 Cybersecurity Program (1) (3)

Identify and assess internal and external cybersecurity risks that may threaten the security or integrity of Nonpublic Information stored on the Covered Entity’s Information Systems.

LANGuardian includes both an intrusion detection system (IDS) and and advanced network traffic analysis engine. This allows you to spot rogue devices on the network as well as providing the ability to generate alerts when cybersecurity events are detected.

Information Security—500.3 (a)

Being able to protect the sensitive and confidential information hosted on systems is critical in the financial industry. You must have a policy in place that allows you to identify who should have access to sensitive information. When a security breach takes place, you need to see what the bad actors have gained access to and what saw. Finally, you need to be able to prove if somebody outside of your authorized list accessed the sensitive information.

LANGuardian can monitor network actvity both inside and at the network edge. No need for agent or client software and because it is not inline it will not impact on the performance of your network. The image below shows an sample LANGuardian report which is listing what users accessed certain files on a network share.

Systems and Network Security—500.3 (g)

When it comes to systems and network security, there should be a policy that defines what security tools are in place and the protections that they offer. What tools do you have in place, and how do you know what security functions they provide? Regardless of the tools, you need to define a policy outlining how the tools protect your sensitive information.

The image below shows how LANGuardian highlighted a suspicous network scan originating from an external IP address. In this case we would use LANGuardian to firstly identify when the scanning started and if the external clients accessed any other systems on the network. Based on this forensic analysis we would then take an appropiate action like block certain ports on the firewall.

Systems and Network Monitoring—500.3 (h)

To enforce the policies of systems and network security, active surveillance and analysis of network systems are required. Without baselining user and traffic behavior, network and security teams are blind to network activity. You need to have an exhaustive record of normal traffic patterns, and you must set up a system that alerts when traffic deviates.

LANGuardian uses a combination of metadata capture and network based intrusion detection to monitor network traffic on a network. It does not age data, so you can look back at historical data in the event of a security breach. The image below shows a LANGuardian report which lists what clients were making outbound connections from a network.

Incident Response—500.3 (n)

The main goal in any incident response and forensic threat investigation solution is to provide teams with the ability to respond quickly to incidents. With that in mind, using such a solution provides organizations with the ability to respond quickly to threats and discover where they’ve gone.

LANGuardian can generate email alerts, or export alerts as SYSLOG events, which can be picked up by SIEM systems. The image below shows a sample of event types that can be triggered by LANGuardian.

What is SMBLoris?

SMBLoris is a memory-handling bug which was revealed last week at DEF CON. Infosec researcher, Jenna Magius provided more details about the bug on her Twitter feed. The vulnerability affects every version of the SMB protocol and every Windows version dating back to Windows 2000. Initial reports suggested that SMBLoris was only associated with SMBv1 but this is not the case.

The SMBLoris attack is able to allocate all available memory that a server has, to the point where it won’t even blue screen, and eventually the operating system crashes. It can also prevent logging on to the server because there’s no memory available. If you reboot the server, log files will be of no use if you need to figure out what clients targeted your server.

What you need to do to prevent SMBLoris attacks?

Microsoft have not released a patch for this vulnerability and their advice is to block access from the internet to SMB servers. SMB typically runs over TCP ports 445 and 139.

It is possible to launch an internal attack, so you should also watch out for any network scanning on your network over TCP ports 445 or 139. It could be a sign of a compromised client seeking out active SMB servers.

Using LANGuardian to check for suspicious SMB activity

Our LANGuardian product passively captures network traffic via SPAN, mirrors ports or TAPs. It then analyzes this traffic and captures metadata such as IP addresses, application protocols and versions, user names, file and folder names, web domains and URIs. When it comes to spotting SMBLoris activity, there are two things to watch out for:

Identify Inbound traffic on TCP port 445 or 139

Use the LANGuardian Top Clients report to focus on network traffic where the client IP address is outside your network, and the destination port is TCP 445 or 139. If you get results in the report, then you should block the clients shown if you are not familiar with them or block all inbound access on these SMB ports.

The screenshot below shows an example where a client with an IP address registered in Russia has established connections to servers inside the perimeter firewalls.

Check for any network scanning on TCP ports 445 or 139

The greatest risk with SMBLoris is with external clients targeting SMB servers hosted locally on your network. However, there is still a risk that a compromised client on your network could bring down your SMB servers. Watch out for any scanning activity associated with TCP ports 445 or 139. It can be a sign of a client generating an inventory of what SMB servers exist on a network.

Use the LANGuardian Network Scanners by Port report to focus in on any scanning activity locally on your network. The screenshot below shows an example of the output of this report. In this case, we do not see any suspicious SMB scanning activity.

The video below shows how you can check your network traffic for any suspicious SMBLoris activity.

If you would like to audit your network, then go ahead and download a 30 day free trial of LANGuardian today.  You have the option to deploy it as a physical or virtual machine, and there are no changes required on your files servers.

A few weeks ago, we held yet another successful customer event, this time in Central London, on Fenchurch Street – which by the way is a terrific location for an event! This event brought together a community of our customers to network and collaborate on our latest LANGuardian release.

The event kicked off with welcoming comments from myself, followed by a number of dynamic presentations which were jointly delivered by our Technical Director, Darragh Delaney and myself. Throughout the half-day event, we presented the latest features in LANGuardian, shared our road map and gave an overview of our technical integrations along with several product demonstrations.

We love to host such customer events, as it gives us the opportunity to share our recent announcements, meet our customers face-to-face and listen to their feedback on what they would like to see in future product developments. Additionally, we were on hand to answer any critical issues from novice and experienced users alike.

A wide range of training topics were delivered throughout the morning, ranging from:

• Creating a Ransomware Monitoring Dashboard
• How to detect SMBv1 use on your network
• How to use the Direct Packet Capture option on LANGuardian, so that it saves packets from a flow when a particular trigger is asserted
• How to use our DNS Traffic Decoding feature to collect DNS queries for all running sensors

We were thrilled with the post-event feedback, so I thought I would share a small sample of this here:

• “It was all good, very informative” – Infrastructure Support Specialist, Financial & Insurance Services
• “I thought it was great overall, although it could be a whole-day training session with more hands-on” – R&D and Infrastructure Engineer, Managed IT Outsourcing
• “The most useful part of this training for me was the demos, especially for Ransomware + DDoS” – Infrastructure Operations Manager, Housing Association
• “Very useful, would be good to have it on an annual basis. We were very impressed with the communications on the WannaCry outbreak; it was very useful” – Network Technician, UK University

Are you a NetFort customer who would like to attend our next event?
Watch out for our upcoming events on our website, community forum or email aisling.brennan@netfort.com to register your interest.

Thanks!

Patch your Windows systems to remove one attack vector for Petya Ransomware

It is critial that you address Microsoft Security Bulletin MS17-010 and patch all Windows clients on your network. Microsoft have published a good post at this link which more background on this and also includes some information on what they are doing to prevent the spread of this Ransomware.

Petya or Petrwap is spreading by exploiting an NSA-built Windows exploit known as “Eternal Blue” which targets the SMBv1 protocol. While SMBv1 is a legacy protocol, it is still available in the latest Microsoft operating systems including:

• Windows XP (all services pack) (x86) (x64)
• Windows Server 2003 SP0 (x86)
• Windows Server 2003 SP1/SP2 (x86)
• Windows Server 2003 (x64)
• Windows Vista (x86)
• Windows Vista (x64)
• Windows Server 2008 (x86
• Windows Server 2008 R2 (x86) (x64)
• Windows 7 (all services pack) (x86) (x64)

In parallel to applying the patch, you should disable SMBv1 use on your network. You can do this by running these commands in Power Shell on each system. Further information on how to disable SMBv1 on other systems are available here.

• Check for SMBv1
  • Get-SmbServerConfiguration | Select EnableSMB1Protocol
• To disable SMBv1 on the SMB server
  •    Set-SmbServerConfiguration -EnableSMB1Protocol $false

Create a read only file called C:\Windows\perfc

A researcher called Amit Serper discovered that NotPetya/Petya/Petna would search for a local file and would exit its encryption routine if that file already existed on disk.

To vaccinate your computer so that you are unable to get infected with the current strain of this Ransomware simply create a file called perfc in the C:\Windows folder and make it read only. If you are unsure how to do this, follow this guide or follow the steps in the video below.

Avoid giving users administrator access

Peyta \ GoldenEye first encrypts the files on the computer and then tries to install the MBR bootkit to encrypt the drive’s MFT. The GoldenEye variant starts by encrypting the user’s files, just like regular ransomware. For each file it encrypts, GoldenEye appends a random 8-character extension at the end.

The ransomware then modifies the user’s hard drive MBR (Master Boot Record), with a custom boot loader. Petya \GoldenEye ransomware must obtain administrative permissions to overwrite a computer’s MBR (Master Boot Record). Make sure you limit what users have administrator access to the network and local PCs’. You can use the Microsoft Local Administrator Password Solution (LAPS) to manage the local account passwords of domain-joined computers.

Once it gains administrator access on a machine, it then leverages that power to commandeer other computers on the network or sniff domain admin credentials present in memory to take control over the entire Windows network.

Check for suspicious traffic flows on your network

You also should review your network traffic flows for any activity associated with Microsoft SMB ports and external addresses. SMB typically uses TCP port 445 and this is one of the main attack vectors used for recent Ransomware attacks. You can monitor network traffic by using SPAN or mirror ports off your core switches.

The image below is an example of what to watch out for. I used a Top Clients report from our LANGuardian product to show all connections over TCP port 445 where the client IP address was external. Based on this data I need to make sure the target machines are not running SMBv1 and I will also block TCP 445 access on my firewall.

Infected machines may also scan the network looking for other Microsoft clients. Watch out for the following behaviour

• Workstations scanning ports tcp/139 and tcp/445 on their own local (/24) network scope
• Servers (in particular, domain controllers) scanning ports tcp/139 and tcp/445 across multiple /24 scopes

How to passively detect SMBv1 use on your network

Even if you think you have patched all systems on your network, you should still run an audit to check for any activity associated with SMBv1. Some network devices may have embedded operating systems which could easily be missed. One method to do this is to use network traffic analysis to detect the presence of clients attempting to connect to other systems using SMBv1.

Our own LANGuardian product can be used to report on SMBv1 use and an example of this is shown in the video below.

We will continue to update this post as we learn more about this Ransomware variant.

Other indicators of Petya \ NoPetya

Watch out for any activity on your network associated with these IP addresses. Check any local systems on your network if they are trying to connnect to these or if you have any inbound activity through your firewall(s) associated with them.

• 95.141.115.108
• 185.165.29.78
• 84.200.16.242
• 111.90.139.247

Why you need to watch out for traffic going in and out of your network

One of the most common requests from customers at the moment is the need to create LANGuardian reports which show what network traffic is entering and leaving their network. The recent WannaCry Ransomware outbreak has really made this type of reporting vital for all Network and Security Managers. WannaCry actively scanned for networks which had TCP port 445 opened and then used a vulnerability in SMBv1 to access network file shares.

Leaving Ransomware to one side, it is always good practice to keep a very close eye on your network perimeter. Even if you have a very good Firewall, mistakes can happen and rogue traffic will get through or users will use various methods including tunneling, external anonymizers and VPNs to get around firewall rules.

Defining what is your network edge

Typically, your network edge perpetrates the local subnets on your network from all the external subnets out on your network. Many of you will use private addresses internally, but it is not uncommon to find public IP blocks in use as well. In order to report on what is entering and leaving your network, you need to define what subnets are in use. If you only use private address ranges then your internal networks could be represented as this list of subnets.

10.0.0.0/8,192.168.0.0/16,172.16.0.0/12

Creating subnet variables for use with LANGuardian reports

While you can use subnets directly within LANGuardian reports, you can save some time in the long run by using report variables. Click on the gear symbol top right and select Customization. From here, click on Report Variables and then Add New Report Variable.

• Create a variable called External by using the subnet filter !10.0.0.0/8,192.168.0.0/16,172.16.0.0/12
• Create a variable called Internal by using the subnet filter 10.0.0.0/8,192.168.0.0/16,172.16.0.0/12

Note that you will need to change the subnet lists above if you use public IP blocks inside your network. Just add them to the list using comma separators.

Top Tip: Add all of your remote sites and VLAN subnets as report variable to speed up troubleshooting. You can quickly see what applications are hogging bandwidth on WAN links by using LANGuardian to focus on traffic associated with the relevant subnet ranges.

Creating custom LANGuardian reports to focus on network edge activity

There are two reports I recommend you look at when it comes to network edge activity.

1. Top external clients connecting inbound to my network
2. Internal to External traffic flows

The steps to create a custom Internal to External report are as follows:

1. Use the Search box to locate the Bandwidth :: Sessions report.
2. Click on the Source IP/Subnet field and select Internal
3. Click on the Destination IP/Subnet field and select External
4. Click Run Report
5. When LANGuardian displays the report, click Actions on the report menu bar and select Save As.
6. Enter a Name and Description, then click Save.

The new report will be listed in the My Reports section.

Take a read of this blog post, if you would like to learn more on how to monitor network traffic on your network. It contains some handy tips on how to get visibility as to what is happening inside your network.