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             AUSCERT External Security Bulletin Redistribution

        K30911244: Advanced WAF, BIG-IP ASM, and NGINX App Protect
                      attack signature check failure
                               23 April 2022


        AusCERT Security Bulletin Summary

Product:           BIG-IP Advanced WAF and ASM
Publisher:         F5 Networks
Operating System:  Network Appliance
Resolution:        Patch/Upgrade

Original Bulletin: 

Comment: CVSS (Max):  None available when published

Revision History:  April   23 2022: Vendor added fixed versions for BIG-IP
                   January 21 2022: Initial Release

- --------------------------BEGIN INCLUDED TEXT--------------------

K30911244: Advanced WAF, BIG-IP ASM, and NGINX App Protect attack signature
check failure

Original Publication Date: 19 Jan, 2022
Latest   Publication Date: 20 Apr, 2022

Security Advisory Description

The F5 Advanced Web Application Firewall (Advanced WAF), BIG-IP ASM, and NGINX
App Protect attack signature check may fail to detect and block certain HTTP
requests when some signatures are disabled on the security policy and wildcard


The attack signature check fails to detect and block such requests, as expected
of a security policy.


As a result of this issue, you may encounter the following symptom:

  o Requests that should have been blocked by the Advanced WAF, BIG-IP ASM, or
    NGINX App Protect systems are received by the back-end server.

Security Advisory Status

F5 Product Development has assigned ID 1019853 (BIG-IP) and WAFMC-4672 (NGINX
App Protect) to this issue. This issue has been classified as CWE-697:
Incorrect Comparison.

To determine if your product and version have been evaluated for this issue,
refer to the Applies to (see versions) box. To determine if your release is
affected by this issue and for information about releases, point releases, or
hotfixes that address the issue, refer to the following table. For more
information about security advisory versioning, refer to K51812227:
Understanding security advisory versioning.

Note: After a fix is introduced for a given minor branch, that fix applies to
all subsequent maintenance and point releases for that branch, and no
additional fixes for that branch will be listed in the table. For example, when
a fix is introduced in, the fix also applies to, and all
later 14.1.x releases (14.1.3.x., 14.1.4.x). For more information, refer to
K51812227: Understanding security advisory versioning. Additionally, software
versions preceding those listed in the Applies to (see versions) box of this
article have reached the End of Technical Support (EoTS) phase of their
lifecycle and are no longer evaluated for security issues. For more
information, refer to the Security hotfixes section of K4602: Overview of the
F5 security vulnerability response policy.

|Product                 |Branch|Versions affected by this   |Fixes introduced|
|                        |      |issue^1                     |in              |
|                        |16.x  |16.1.0 - 16.1.1             |16.1.2          |
|                        +------+----------------------------+----------------+
|                        |15.x  |15.1.0 - 15.1.4             |        |
|                        +------+----------------------------+----------------+
|BIG-IP (Advanced WAF,   |14.x  |14.1.0 - 14.1.4             |        |
|ASM)                    +------+----------------------------+----------------+
|                        |13.x  |13.1.0 - 13.1.4             |13.1.5          |
|                        +------+----------------------------+----------------+
|                        |12.x  |None                        |Not applicable  |
|                        +------+----------------------------+----------------+
|                        |11.x  |None                        |Not applicable  |
|                        |16.x  |None                        |Not applicable  |
|                        +------+----------------------------+----------------+
|                        |15.x  |None                        |Not applicable  |
|                        +------+----------------------------+----------------+
|BIG-IP (all other       |14.x  |None                        |Not applicable  |
|modules)                +------+----------------------------+----------------+
|                        |13.x  |None                        |Not applicable  |
|                        +------+----------------------------+----------------+
|                        |12.x  |None                        |Not applicable  |
|                        +------+----------------------------+----------------+
|                        |11.x  |None                        |Not applicable  |
|BIG-IQ Centralized      |8.x   |None                        |Not applicable  |
|Management              +------+----------------------------+----------------+
|                        |7.x   |None                        |Not applicable  |
|F5OS-A                  |1.x   |None                        |Not applicable  |
|F5OS-C                  |1.x   |None                        |Not applicable  |
|                        |3.x   |3.0.0 - 3.6.0               |3.7.0           |
|                        +------+----------------------------+----------------+
|NGINX App Protect       |2.x   |2.0.0 - 2.3.0               |None            |
|                        +------+----------------------------+----------------+
|                        |1.x   |1.0.0 - 1.3.0               |None            |

^1F5 evaluates only software versions that have not yet reached the End of
Technical Support (EoTS) phase of their lifecycle.

Recommended Actions

If you are running a version listed in the Versions affected by this issue
column, you can eliminate this issue by installing a version listed in the
Fixes introduced in column. If the Fixes introduced in column does not list a
version for your branch, then no update candidate currently exists for that
branch and F5 recommends upgrading to a version with the fix (refer to the

If the Fixes introduced in column lists a version prior to the one you are
running, in the same branch, then your version should have the fix.


To mitigate this issue, you can remove the disabled signature from the wildcard
header and disable these signatures on the security policy instead.

Impact of action: Performing the mitigation should not have a negative impact
on your system.


This issue was discovered internally by F5.

Supplemental Information

o K51812227: Understanding security advisory versioning
  o K41942608: Overview of AskF5 security advisory articles
  o K4602: Overview of the F5 security vulnerability response policy
  o K4918: Overview of the F5 critical issue hotfix policy
  o K8986: F5 software lifecycle policy
  o K9502: BIG-IP hotfix and point release matrix
  o K13123: Managing BIG-IP product hotfixes (11.x - 16.x)
  o K167: Downloading software and firmware from F5
  o K9970: Subscribing to email notifications regarding F5 products
  o K9957: Creating a custom RSS feed to view new and updated documents

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