Securing Your Applications with F5 BIG-IP IDS/IPS
Introduction Are you taking advantage of F5 BIG-IP’s built in IDS/IPS?IDS systems monitor traffic for anomalies, where IPS systems react to those events. Since BIG-IP version 13.1.0, you have had the ability to process traffic running through your BIG-IP with an IPS/IDS engine that we call Protocol Inspection. Enabling IDS/IPS on your BIG-IP will allow you to increase your defense-in-depth posture using your existing BIG-IP investment. This is the first article in the series where I will provide background and describe the features and functionality. The following articles will review: Features and functionality Deep dive into features Configurations and best practices Background First, some details explaining the differences and how F5 fits in the puzzle. Intrusion detection systems (IDS) are passive devices that monitor and log events on the network and can be configured to send alerts to an Administrator. These IDSs come in Network IDSs and Host based IDSs. This article will focus on Network based IDSs. Intrusion preventions systems (IPS) on the other hand have response capabilities. The responses range from dropping traffic, resetting the connection or passing the traffic to a sandboxed environment. The terms are used interchangeably, by most, so from now on I will refer to the systems as IDS/IPS. These IDS/IPS devices are usually placed in strategic ingress or egress locations such as security zones, data centers orthe edge of the network to capture and analyze critical traffic. Generally, these systems operate on signatures developed from known attacks or custom rules, protocol analysis and content matching. If your organization is running a BIG-IP, it most likely sits in one of these strategic locations within your network, protecting your most valuable assets. This enables you to take advantage of the built-in functionality of BIG-IP IDS/IPS engine instead of passing off the process to a 3rd party device which adds additional latency. The BIG-IP IDS/IPS capability is delivered as two major features: Protocol Inspection Engine Subscription Service BIG-IP Advanced Firewall Manager and Protocol Inspection BIG-IP’s Advanced Firewall Manager (AFM) is the module that allows you to take advantage of the IDS/IPS feature. When enabled, the Protocol Inspection Engine does both application protocol compliance checks and signature matching. The concept behind protocol match is the following: Drop traffic if it does not conform to protocol standards Drop traffic based on a signature match The versatility of the BIG-IP allows Protocol inspection to be applied as an AFM rule to all contexts (global/route/domain or virtual server) or directly to a virtual server.The beauty of this approach is in the processing of traffic.You can inspect the traffic pre-decryption or post- decryption based on polices, politics, or design. Want to step it up a notch further?Apply it to both an AFM rule and a virtual server. Protocol Inspection offers several features and functionality including the following: Granular Protocol Compliance Checks TCP, SCTP and UDP Signatures Learning and Staging Subscription Service Protocol Inspection and Signature Updates Granular Protocol Compliance Checks At the heart of F5s IDS/IPS is the Protocol Inspection Profile, seen below: After naming the profile, you have all the configuration options available to you. You enable or disable if this profile uses signatures, compliance checks, if will you collect stats for reporting in Application Visibility Reporting (AVR) and what services you are inspecting. We support 30 services currently. When you select one or multiples of services to inspect, you will have the option to see and further refine which signatures are used. Additional configuration selections of Suggestion Properties and Update Settings will be covered in another article. Signatures The F5 signatures are based on a subset of Snort rules syntax. When looking at signatures, you will notice they have been assigned a classification or grouping based on what the exploit is attempting to execute (see below): Additionally, signatures are broken down and grouped into “services” to assist in finding the specific signature you might look for. Drilling even further down into an exploit/signature, you can click the signature name and additional information becomes available. I’d like to call attention to the Last Refreshed date and the Hyperlinks to the References; CVE and Bugtraq ID. The Last Refreshed date indicates when the signature was last modified. Clicking either hyperlink takes you to the related article. Here is an example of the CVE article. Here is an example of the Bugtraq article. Subscription Service When AFM is initially downloaded and installed it comes with a base set of protocol inspections and signatures. In order to take advantage and receive regular timely updates to both the protocol inspection profiles and signatures, you need to add the IPS Subscription Service. Protocol Inspection and Signature Updates AFM allows the ability to manually check for and import updated files when you decide or have time. Or for the easy button, the ability to automatically check, download and deploy updated for updated files. You have the option to select whether to “Download” or “Download and Deploy” and the frequency of updating, daily, weekly or monthly. Additionally, you get visibility into what is available to install and what is available to deploy. . Review the example screenshot below. Summary In this article we discussed the features and functionality of BIG-IP AFMs IDS/IPS, configuration and updates of the Protocol Engine and signatures. In the next article we will look deeper into protocol compliance, inspections and signatures. Appendix Advanced Firewall Manager Datasheet Advanced Firewall Manager Operation Guide AFM Intrusion Prevention SystemsEnhance your Application Security using Client-side signals – Part 2
Elevate your web and mobile application security with F5's innovative integration of web proxy strategies and client-side signals in this two-part series. Dive into the three critical categories of client-side signals—human interaction, device environment, and network signals—to enhance your application security strategy. Gain practical insights on distinguishing between humans and bots, fingerprinting devices, and analyzing network signals, ensuring robust protection for your online applications.Orchestrated Infrastructure Security - Getting Started
Note:TheBeaconcapabilities referenced in this article hosted on F5 Cloud Services are planning a migration to a new SaaS Platform - Check out the latesthere. Introduction A typical daisy-chained security stack is difficult to manage and make changes.All devices in the chain are physically wired to each other in a serial arrangement.Each device performs SSL decryption and re-encryption when needed.All devices in the chain need to have similar performance capabilities.All devices in the chain need to be properly configured to route traffic to their neighboring devices, and likely will need to be manually configured to trust SSL certificates used by neighboring devices for decryption and re-encryption. Failure of any device in the security chain brings the entire chain down.Capacity cannot be increased simply by adding another like-device (i.e. a NGFW) to the chain.Capacity can only be increased by replacing a single device with a higher capacity device. Removing or adding a device to the chain is problematic.For one, the entire security stack will need to be unavailable while removing or adding a device.Proper routing between devices must be maintained or the whole chain will not pass traffic.Certificate trust and other factors may need to be addressed as well. High availability is also problematic.The only way to ensure high availability is to create another daisy-chain, identical to the first.This chain needs to wait in standby mode until the primary chain fails or is taken down, and then the standby chain can take over for the primary. Managing a single daisy chain security stack is not easy.Managing two for high availability is significantly more complicated and overly expensive. Some security devices are deployed differently and cannot operate together in the security stack.Those devices would need their own separate deployment from the devices in the daisy chain, further complicating the configuration.As an example, it’s not an uncommon security practice to employ network TAP devices, explicit proxies, ICAP servers as well as Layer2/3 devices. All of these devices cannot be configured to properly route traffic in a daisy chain. SSL Orchestrator solves almost all of these challenges, and enables you to have a nimble security solution capable of adapting to almost any type of threat. High Level Network Topology The network topology used for this setup is below.BIG-IP-11 and 12 are deployed in Layer 2 mode. The Advanced WAF and AFM devices will also be deployed in Layer 2 and will be physically wired to the SSL Orchestrators.This is a high availability environment where there is one Active BIG-IP and one ready on Standby.The Port Objects (511 & 512) allow traffic to flow through either BIG-IP, in case of a failure.The applications being protected are represented by the Ubuntu servers connected to the South switch. BIG-IP Network Topology A zoomed in view of the BIG-IP devices is below.This shows the physical connectivity and the specific interfaces used by SSL Orchestrator, Advanced WAF and AFM devices. Summary This article is part of a series on implementing Orchestrated Infrastructure Security. It includes High Availability, Central Management with BIG-IQ, Application Visibility with Beacon and the protection of critical assets using F5 Advanced WAF and Protocol Inspection (IPS) with AFM.It is assumed that SSL Orchestrator is already deployed, and basic network connectivity is working. Next Steps Click Next to proceed to the next article in the series.Orchestrated Infrastructure Security - Protocol Inspection with AFM
The F5 Beacon capabilities referenced in this article hosted on F5 Cloud Services are planning a migration to a new SaaS Platform - Check out the latesthere. Introduction This article is part of a series on implementing Orchestrated Infrastructure Security. It includes High Availability, Central Management with BIG-IQ, Application Visibility with Beacon and the protection of critical assets using F5 Advanced WAF and Protocol Inspection (IPS) with AFM.It is assumed that SSL Orchestrator is already deployed, and basic network connectivity is working. If you need help setting up SSL Orchestrator for the first time, refer to the Dev/Central article series Implementing SSL Orchestrator here. This article focuses on configuring Protocol Inspection (IPS) with AFM deployed as a Layer 2 solution. It covers the configuration of Protocol Inspection on an F5 BIG-IP running version 16.0.0. Configuration of BIG-IP deployed as AFM can be downloaded from here from GitLab. Please forgive me for using SSL and TLS interchangeably in this article. This article is divided into the following high level sections: Protocol Inspection (IPS) with AFM Network Configuration Create an AFM Protocol Inspection Policy Attach Virtual Servers to an AFM Protocol Inspection Policy Protocol Inspection (IPS) with AFM: Network Configuration The BIG-IP will be deployed with VLAN Groups.This combines 2 interfaces to act as an L2 bridge where data flows into one interface and is passed out the other interface. From the F5 Configuration Utility go to Network > VLANs.Click Create on the right. Give it a name, ingress1 in this example.Set the Interface to 5.0.Set Tagging to Untagged then click Add.Interface 5.0 (untagged) should be visible like in the image below.Click Repeat at the bottom to create another VLAN. Note: In this example interface 5.0 will receive decrypted traffic from sslo1. Give it a name, egress1 in this example.Set the Interface to 6.0.Set Tagging to Untagged then click Add.Interface 6.0 (untagged) should be visible like in the image below.Click Finished when done. Note: In this example interface 6.0 will receive decrypted traffic from sslo1. Note: This guide assumes you are setting up a redundant pair of SSL Orchestrators.Therefore, you should repeat these steps to configure VLANs for the two interfaces connected to sslo2.These VLANs should be named in a way that you can differentiate them from the others.Example: ingress2 and egress2 It should look something like this when done: Note: In this example Interface 3.0 and 4.0 are physically connected to sslo2. Click VLAN Groups then Create on the right. Give it a name, vlg1 in this example.Move ingress1 and egress1 from Available to Members.Set the Transparency Mode to Transparent.Check the box to Bridge All Traffic then click Finished. Note: This guide assumes you are setting up a redundant pair of SSL Orchestrators. Therefore, you should repeat these steps to configure a VLAN Group for the two interfaces connected to sslo2.This VLAN Group should be named in a way that you can differentiate it from the other, example: vlg1 and vlg2.It should look like the image below: For full Layer 2 transparency the following CLI option needs to be enabled: (tmos)# modify sys db connection.vgl2transparent value enable Create an AFM Protocol Inspection Policy You can skip this step if you already have an AFM Protocol Inspection policy created and attached to one or more virtual servers.If not, we’ll cover it briefly.In this example we configured Protocol Inspection with Signatures and Compliance enabled. From Security select Protocol Security > Inspection Profiles > Add > New. Give it a name, IPS in this example.For Services, select the Protocol(s) you want to inspect, HTTP in this example. Optionally check the box to enable automatic updates and click Commit Changes to System. Attach Virtual Servers to an AFM Protocol Inspection Policy Attach the Protocol Inspection Profile to the Virtual Server(s) you wish to protect.From Local Traffic select Virtual Servers.Click the name of the Virtual Server you want to apply the profile to, 10.4.11.52 in this example. Click Security > Policies. Set the Protocol Inspection Profile to Enabled, then select the Profile created previously, IPS in this example.Click Update when done. Repeat this process to attach the IPS Profile to the remaining Virtual Servers. Summary In this article you learned how to configure BIG-IP in layer 2 transparency mode using VLAN groups.We also covered how to create an AFM Protocol Inspection policy and attach it to your Virtual Servers. Next Steps Click Next to proceed to the next article in the series.
Converting a Snort Rule to an AFM Protocol Inspection Custom Signature
We recently had the opportunity to demonstrate what I consider the most interesting use case for Protocol Inspection custom signatures: adapting existing Snort rules for use in AFM Protocol Inspection. Security company FireEye announced a breach in which the tools used by their red teams to test network and application defenses were stolen. FireEye released Snort rules to identify traffic associated with the command and control of these tools. We ported these Snort rules to AFM Protocol Inspection custom signatures and published them in F5's Guidance.https://devcentral.f5.com/s/articles/F5-SIRT-FireEye-Breach-Guidance The reason I find this such a compelling use case is that most of our customers have day jobs. They are not full-time security researchers who model application protocols and swap inside information with other security researchers as a profession. However, we can leverage the work of those who do have those jobs and adapt the Snort rules they write for use with AFM Protocol Inspection. That's exactly what we've done here and I'll show you the process we used to do it. General Observations First, I want to describe the relationship between a Snort rule and a Protocol Inspection custom signature. Basically, the detection syntax is the same, but everything else is different. Both provide tons of useful meta-data, but how that is provided by the two systems is different. Another thing to think about is preservation of information. I don't want my custom signature to lose any information present in the Snort rule. At a minimum, you will want to record where the custom signature came from. I recommend recording the source of the Snort rule in your custom signature in the references or reference-links fields, and retain anything that might provide a breadcrumb to your incident response, such as the Snort rule's msg , reference , and metadata field contents. If you can preserve the Snort rule'ssid by the use of prefixes or suffixes in the custom signature'sid , that might help an incident responder track down the original Snort rule. I'll show one approach to doing this in my conversion below. The Snort Signature - what we're adapting We'll adapt the following signature, provided by FireEye under a BSD license (see below): alert tcp any $HTTP_PORTS -> any any (msg:"Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]"; flow:from_server,established; content:"{\"meta\":{},\"status\":\"OK\",\"saved\":\"1\",\"starttime\":17656184060,\"id\":\"\",\"vims\":{\"dtc\":\""; sid:25888; rev:1;) Signature Creation walk-through Here's how I built out one Snort rule conversion into a custom signature. We'll go field by field, building out the command and editing as we go. The added or changed sections at each step will be in bold. I put a comparison of Snort rule elements and custom signature fields after the walk-thru if you want details on each step. I have a tmsh session open on the BIG-IP, in the security.protocol-inspection.signature context, and a Snort rule I can cut from to paste into my tmsh session. The first field I need is the custom signature name. I will use the msg field from the Snort rule as the basis for the name . This follows the convention for importing signatures from a file. I copy the Snort rulemsgfield, Backdoor.HTTP.BEACON.[CSBundle MSOffice Server], omitting the starting and ending quotation marks. I need to remove the brackets and remove or replace the spaces to use in the name. My convention is to remove prohibited characters and swap underscore characters for spaces. create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server I can use the Snort rule msg unchanged for the description so long as I enclose it in quotes, and since it's in the copy buffer I'll add that field to my command next. create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server description "Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]" Now theprotocolfield. This has to take the form of a list enclosed in curly braces. I take it from the protocol specified in the Snort rule's header. create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server description "Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]" protocol {tcp} Now thereferencesand reference-links. I took these from the web page announcing the issue the Snort rules address. create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server description "Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]" protocol {tcp} references "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" reference-links "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" Now the service, which is a mandatory field. I infer this is http from the Snort rule header section $HTTP_PORTS and the "HTTP" string in the msg. If you do not specify a service, the "other" service is selected for you. create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server description "Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]" protocol {tcp} references "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" reference-links "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" service http I derive theidfrom the Snort rulesid25888. I'll prepend a 1 to bring it into the 100000+ range used for custom signatures. Because we have the references filled out, this is not critical. In fact, you could preserve the original Snort rulesidin the documentation section and just let the system assign the next available id number. create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server description "Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]" protocol {tcp} references "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" reference-links "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" service http id 125888 Specifying thedirectioncan reduce log spam and misleading stats. For example, if you are interested in requests for http://mysite.example.com/../../etc/passwd but don't care about 404 errors in response, specify thedirectionto-server. That way only traffic to the server will match. In this case, our Snort rule's direction is to-client, which I infer from the Snort header source port being $HTTP_PORTS. create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server description "Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]" protocol {tcp} references "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" reference-links "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" service http id 125888 direction to-client Now we get to the good stuff: the sig field. I add sig " to my signature. sig is a container for pcre and content checks, and the container is delimited by UNESCAPED quotation marks. create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server description "Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]" protocol {tcp} references "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" reference-links "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" service http id 125888 direction to-client sig " I copy the payload detection elements from the Snort rule - all the content and pcre checks - and paste that in. create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server description "Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]" protocol {tcp} references "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" reference-links "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" service http id 125888 direction to-client sig "content:"{\"meta\":{},\"status\":\"OK\",\"saved\":\"1\",\"starttime\":17656184060,\"id\":\"\",\"vims\":{\"dtc\":\""; I add a double-quote character to the end, to identify the end of the sig field. This should NOT be escaped. create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server description "Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]" protocol {tcp} references "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" reference-links "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" service http id 125888 direction to-client sig "content:"{\"meta\":{},\"status\":\"OK\",\"saved\":\"1\",\"starttime\":17656184060,\"id\":\"\",\"vims\":{\"dtc\":\"";" I then go through and escape the quotation marks at the beginning and end of every content and pcre check with a backslash. Note I can ignore quotation marks already escaped inside these content and pcre checks. These added backslashes are in red for slightly easier identification. create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server4 description "Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]" protocol {tcp} references "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" reference-links "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" service http id 125888 direction to-client sig "content:\"{\"meta\":{},\"status\":\"OK\",\"saved\":\"1\",\"starttime\":17656184060,\"id\":\"\",\"vims\":{\"dtc\":\"\";" Now I can hit the 'Enter' key and my custom signature will be added. I can then select and enable it in Protocol Inspection policies. One note: the validation for custom signatures is letting me get away with a lot because I'm using BIG-IP v16.0.0. 14.x will not tolerate a signature definition that includes characters that are used in Snort syntax. It's a good practice to use the hexadecimal representation even in 16x. Here's what that would look like: create Backdoor.HTTP.BEACON.CSBundle_MSOffice_Server4 description "Backdoor.HTTP.BEACON.[CSBundle MSOffice Server]" protocol {tcp} references "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" reference-links "https://www.fireeye.com/blog/threat-research/2020/12/unauthorized-access-of-fireeye-red-team-tools.html" service http id 125888 direction to-client sig "content:\"{|22|meta|22 3a|{},|22|status|22 3a 22|OK|22|,|22|saved|22 3a 22|1|22|,|22|starttime|22 3a|17656184060,|22|id|22 3a 22 22|,|22|vims|22 3a|{|22|dtc|22 3a 22|\";" Copyright 2020 by FireEye, Inc. The 2-Clause BSD License Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. For more information on Protocol Inspection Custom Signatures, see K00322533 Overview of Protocol Inspection Custom SignaturesMitigating log4j (CVE-2021-44228) with AFM Protocol Inspection Custom Signatures
The Log4j vulnerability has drawn a great deal of attention and I won't recap anything that other people have said better than I can. See https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability and https://support.f5.com/csp/article/K59329043 for background. UPDATE: I recommend using these three signatures based on Regular Expressions/PCRE to detect attacks using padding and different character encoding schemes to disguise the attack. The first signature is redundant and limited in its application, but very low in resource use. The second will catch exploit attempts that use a bewildering variety of alternate character encoding schemes, but is resource intensive. The third is a specialty signature that deems any payload with "Base64" together with " $ " and " { " (however encoded) to be suspect. This third signature is cheap to use. Simple, low-impact signature that handles padding between significant characters but not character encoding. Limited capability compared with the next two signatures, but if it matches it saves the effort of attempting to match other signatures. create log4j-pcre sig "content: \"$\"; content: \"{\"; distance: 1; pcre:\"/(\?i)\\$'\?\\{.*\?j.*\?n.*\?d.*\?i.*\?\\:/s\";" description "Apache Log4j attempt" service http documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability" direction to-server references "CVE-2021-44228" See the related article "Using Perl Compatible Regular Expressions (PCR) in Protocol Inspection Custom Signatures" for a detailed breakdown. Complex signature that checks for a variety of encoding types for each of the significant characters. WARNING: may cause a performance hit because we can't use a content check as a pre-filter. create log4j2-encoded sig "pcre:\"/(\\$|(0\?44|([u0]00|x|(%|%25|[u0]00)78|%|[u0]0025|%25)24))/\"; pcre:\"/\\{|(0\?173|([u0]00|x|170|(%|045|%25|[u0]00)78|%|[u0]0025|%25)7b)/i\";distance: 1;pcre:\"/j|b|1[5140]2|([u0]00|x|170|([u0]00|%|045|%25|x)78)|%|045|(([u0]00|%|%25|x)25)[64][a2]/i\";distance: 1; pcre:\"/n|1[15]6|([u0]00|x|170|([u0]00|%|045|%25|x)78)|%|045|(([u0]00|%|%25|x)25)[46]e/i\";distance: 1; pcre:\"/d|1[04]4|([u0]00|x|170|([u0]00|%|045|%25|x)78)|%|045|(([u0]00|%|%25|x)25)[46]4/i\";distance: 1; pcre:\"/i|1[15]1|([u0]00|x|170|([u0]00|%|045|%25|x)78)|%|045|(([u0]00|%|%25|x)25)[46]9/i\";distance: 1;" description "Apache Log4j2 exploitation attempt encoded" service http attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability" direction to-server references "CVE-2021-44228" Simple and low-impact signature to check for attempts using Base64 encoding create log4j2-base64 sig "content:\"Base64\";nocase; pcre:\"/(\\$|(0\?44|([u0]00|x|(%|%25|[u0]00)78|%|[u0]0025|%25)24))/\"; pcre:\"/\\{|(0\?173|([u0]00|x|170|(%|045|%25|[u0]00)78|%|[u0]0025|%25)7b)/i\";distance: 1;" description "Apache Log4j2 exploitation attempt encoded in Base64" service http attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability" direction to-server references "CVE-2021-44228" End of Update. The following signatures are obsolete due to the use of static content patterns. I took some Snort signatures provided by the RSA SOC Prime team, and ported them (with permission) to AFM Protocol Inspection custom signatures. This is similar to an exercise I performed about a year ago in the wake of the Fireeye breach (see https://devcentral.f5.com/s/articles/Converting-a-Snort-Rule-to-an-AFM-Protocol-Inspection-Custom-Signature). Without belaboring the point, here are the signatures. IMPORTANT: these signatures make no attempt to defeat obfuscation attempts. They are simple string matches. To enable them, start a tmsh session and switch to the security > protocol-inspection > signature context. Then paste these 3-4 at a time, depending on the size of your paste buffer: create ET_EXPLOIT_Apache_log4j_RCE_Attempt-http_ldap description "ET EXPLOIT Apache log4j RCE Attempt (http ldap)" sig "content:\"|24 7b|jndi|3a|ldap|3a 2f 2f|\";nocase;" id 2034647 protocol {tcp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " create ET_EXPLOIT_Apache_log4j_RCE_Attempt-http_rmi description "ET EXPLOIT Apache log4j RCE Attempt (http rmi)" sig "content:\"|24 7b|jndi|3a|rmi|3a 2f 2f|\"; nocase;" id 2034648 protocol {tcp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " create ET_EXPLOIT_Apache_log4j_RCE_Attempt-tcp_ldap description "ET EXPLOIT Apache log4j RCE Attempt (tcp ldap)" sig "content:\"|24 7b|jndi|3a|ldap|3a 2f 2f|\"; nocase;" id 2034649 protocol {tcp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " create ET_EXPLOIT_Apache_log4j_RCE_Attempt-tcp_rmi description "ET EXPLOIT Apache log4j RCE Attempt (tcp rmi)" sig "content:\"|24 7b|jndi|3a|rmi|3a 2f 2f|\"; nocase;" id 2034650 protocol {tcp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " create ET_EXPLOIT_Apache_log4j_RCE_Attempt-udp_ldap description "ET EXPLOIT Apache log4j RCE Attempt (udp ldap)" sig "content:\"|24 7b|jndi|3a|ldap|3a 2f 2f|\"; nocase;" id 2034651 protocol {udp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " create ET_EXPLOIT_Apache_log4j_RCE_Attempt-udp_rmi description "ET EXPLOIT Apache log4j RCE Attempt (udp rmi)" sig "content:\"|24 7b|jndi|3a|rmi|3a 2f 2f|\"; nocase;" id 2034652 protocol {udp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " create ET_EXPLOIT_Apache_log4j_RCE_Attempt-udp_dns description "ET EXPLOIT Apache log4j RCE Attempt (udp dns)" sig "content:\"|24 7b|jndi|3a|dns|3a 2f 2f|\"; nocase;" id 2034662 protocol {udp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " create ET_EXPLOIT_Apache_log4j_RCE_Attempt-tcp_dns description "ET EXPLOIT Apache log4j RCE Attempt (tcp dns)" sig "content:\"|24 7b|jndi|3a|dns|3a 2f 2f|\"; nocase;" id 2034660 protocol {tcp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " create ET_EXPLOIT_Apache_log4j_RCE_Attempt-http_dns description "ET EXPLOIT Apache log4j RCE Attempt (http dns)" sig "content:\"|24 7b|jndi|3a|dns|3a 2f 2f|\"; nocase;" id 2034657 protocol {tcp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " create ET_EXPLOIT_Apache_log4j_RCE_Attempt-udp_ldaps description "ET EXPLOIT Apache log4j RCE Attempt (udp ldaps)" sig "content:\"|24 7b|jndi|3a|ldaps|3a 2f 2f|\"; nocase;" id 2034672 protocol {udp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " create ET_EXPLOIT_Apache_log4j_RCE_Attempt-tcp_ldaps description "ET EXPLOIT Apache log4j RCE Attempt (tcp ldaps)" sig "content:\"|24 7b|jndi|3a|ldaps|3a 2f 2f|\"; nocase;" id 2034670 protocol {tcp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " create ET_EXPLOIT_Apache_log4j_RCE_Attempt-http_ldaps description "ET EXPLOIT Apache log4j RCE Attempt (http ldaps)" sig "content:\"|24 7b|jndi|3a|ldaps|3a 2f 2f|\"; nocase;" id 2034667 protocol {tcp} reference-links "https://community.rsa.com/t5/netwitness-blog/apache-log4j-log4shell-background-and-detection-rules/ba-p/660546?attachment-id=32926" references "RSA SOC Prime Team authored these signatures. CVE-2021-44228" service http direction to-server attack-type attempted-admin documentation "https://www.f5.com/company/blog/protection-against-apache-log4j2-vulnerability https://lunasec.io/docs/blog/log4j-zero-day/ " My thanks to RSA for providing these signatures.
