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             AUSCERT External Security Bulletin Redistribution

         BIG-IP engineering hotfix TMM vulnerability CVE-2020-5852
                              14 January 2020


        AusCERT Security Bulletin Summary

Product:           BIG-IP products
Publisher:         F5 Networks
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Mitigation
CVE Names:         CVE-2020-5852  

Original Bulletin: 

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K53590702:BIG-IP engineering hotfix TMM vulnerability CVE-2020-5852

Security Advisory

Original Publication Date: 14 Jan, 2020

Security Advisory Description

Undisclosed traffic patterns received may cause a disruption of service to the
Traffic Management Microkernel (TMM). This vulnerability affects TMM through a
virtual server configured with a FastL4 profile. Traffic processing is
disrupted while TMM restarts. (CVE-2020-5852)


A remote attacker may be able to cause a BIG-IP system to produce a core file,
disrupting the flow of traffic and causing a failover to a standby system, if
configured. You may observe a notice panic: Assertion "l3hdr set" failed error
message in the /var/log/ltm file when TMM produces a core file and restarts.

Important: This vulnerability impacts only BIG-IP engineering hotfixes obtained
from F5 Support. For the list of affected versions, refer to the table in the
following section. To verify if you are running an affected version from this
list, perform the procedure in the Security Advisory Recommended Actions
section. This vulnerability does not affect any of the BIG-IP major, minor,
maintenance, or point releases obtained from F5 Downloads.

Security Advisory Status

F5 Product Development has assigned ID 834293 (BIG-IP) to this vulnerability.

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

|           |      |                                |Fixes      |          |CVSSv3|Vulnerable|
|Product    |Branch|Versions known to be vulnerable |introduced |Severity  |score^|component |
|           |      |                                |in         |          |1     |or feature|
|           |15.x  |None                            |Not        |          |      |          |
|           |      |                                |applicable |          |      |          |
|           +------+--------------------------------+-----------+          |      |          |
|           |      |                                |Not        |          |      |          |
|BIG-IP     |14.x  |Hotfix-BIGIP-|applicable^|          |      |          |
|(LTM, AAM, |      |                                |2          |          |      |          |
|AFM,       +------+--------------------------------+-----------+          |      |          |
|Analytics, |13.x  |None                            |Not        |          |      |TMM       |
|APM, ASM,  |      |                                |applicable |Medium    |5.9   |(FastL4   |
|DNS, FPS,  +------+--------------------------------+-----------+          |      |profile)  |
|GTM, Link  |      |                                |Not        |          |      |          |
|Controller,|12.x  |Hotfix-BIGIP-|applicable^|          |      |          |
|PEM)       |      |                                |2          |          |      |          |
|           +------+--------------------------------+-----------+          |      |          |
|           |      |                                |Not        |          |      |          |
|           |11.x  |Hotfix-BIGIP-|applicable^|          |      |          |
|           |      |                                |2          |          |      |          |
|           |7.x   |None                            |Not        |          |      |          |
|           |      |                                |applicable |          |      |          |
|BIG-IQ     +------+--------------------------------+-----------+          |      |          |
|Centralized|6.x   |None                            |Not        |Not       |None  |None      |
|Management |      |                                |applicable |vulnerable|      |          |
|           +------+--------------------------------+-----------+          |      |          |
|           |5.x   |None                            |Not        |          |      |          |
|           |      |                                |applicable |          |      |          |
|Traffix SDC|5.x   |None                            |Not        |Not       |None  |None      |
|           |      |                                |applicable |vulnerable|      |          |

^1The CVSSv3 score link takes you to a resource outside of AskF5, and it is
possible that the document may be removed without our knowledge.

^2In this vulnerability, only the listed BIG-IP engineering hotfixes are
affected. This vulnerability does not affect any of the BIG-IP major, minor,
maintenance, or point releases obtained from F5 Downloads.

Security Advisory Recommended Actions

Your BIG-IP system is affected by this vulnerability only when running an
engineering hotfix version listed in the table. To verify your BIG-IP system's
version, perform the following procedure:

Impact of procedure: Performing the following procedure should not have a
negative impact on your system.

 1. Log in to the TMOS Shell (tmsh) by entering the following command:


 2. Display your BIG-IP system's version by entering the following command:

    show /sys version

    If the displayed version is not one of the engineering hotfix versions
    listed in the table, your system is not vulnerable.


After performing the previous procedure, if you determine that your BIG-IP
system is vulnerable, you can obtain an engineering hotfix by contacting F5
Support and referencing this article number and the associated ID number. Note
that engineering hotfixes are intended to resolve a specific software issue
until a suitable minor release, maintenance release, or cumulative hotfix
rollup release is available that includes the software fix. For more
information, refer to K8986: F5 software lifecycle policy.

Supplemental Information

o K51812227: Understanding Security Advisory versioning
  o K41942608: Overview of Security Advisory articles
  o K4602: Overview of the F5 security vulnerability response policy
  o K4918: Overview of the F5 critical issue hotfix policy
  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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