ESB-2018.3075 - [Appliance] F5 BIG-IP products: Denial of service - Remote/unauthenticated 2018-10-11

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             AUSCERT External Security Bulletin Redistribution

                 TMM with LRO vulnerability CVE-2018-15311
                              11 October 2018


        AusCERT Security Bulletin Summary

Product:           F5 BIG-IP products
Publisher:         F5 Networks
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2018-15311  

Original Bulletin:

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

K07550539:TMM with LRO vulnerability CVE-2018-15311

Security Advisory

Original Publication Date: 10 Oct, 2018

Security Advisory Description

When Large Receive Offload (LRO) is enabled, undisclosed traffic patterns may
cause TMM to restart. LRO has been available since 11.4.0 but is not enabled
by default until 13.1.0. (CVE-2018-15311)


An attacker may be able to disrupt traffic or cause the BIG-IP system to fail
over to another device in the device group.

Note:  This vulnerability is not exposed unless Large Receive Offload (LRO) is

Security Advisory Status

F5 Product Development has assigned ID 708653 (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 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.

|                  |      |Versions  |Fixes     |          |CVSSv3|Vulnerable|
|Product           |Branch|known to  |introduced|Severity  |score^|component |
|                  |      |be        |in        |          |1     |or feature|
|                  |      |vulnerable|          |          |      |          |
|                  |14.x  |None      |Not       |          |      |          |
|                  |      |          |Applicable|          |      |          |
|                  +------+----------+----------+          |      |          |
|BIG-IP (LTM, AAM, |13.x  |13.0.0 -  |  |          |      |          |
|AFM, Analytics,   |      |13.1.0    |          |          |      |Large     |
|APM, ASM, DNS,    +------+----------+----------+          |      |Receive   |
|Edge Gateway, FPS,|12.x  |12.1.0 -  |  |Low       |3.7   |Offload   |
|GTM, Link         |      |12.1.3    |          |          |      |(LRO)     |
|Controller, PEM,  +------+----------+----------+          |      |feature   |
|WebAccelerator)   |      |11.6.0 -  |  |          |      |          |
|                  |      |11.6.3    |          |          |      |          |
|                  |11.x  +----------+----------+          |      |          |
|                  |      |11.5.1 -  |11.5.7    |          |      |          |
|                  |      |11.5.6    |          |          |      |          |
|Enterprise Manager|3.x   |None      |Not       |Not       |None  |None      |
|                  |      |          |applicable|vulnerable|      |          |
|                  |6.x   |None      |Not       |          |      |          |
|                  |      |          |applicable|          |      |          |
|                  +------+----------+----------+          |      |          |
|BIG-IQ Centralized|5.x   |None      |Not       |Not       |None  |None      |
|Management        |      |          |applicable|vulnerable|      |          |
|                  +------+----------+----------+          |      |          |
|                  |4.x   |None      |Not       |          |      |          |
|                  |      |          |applicable|          |      |          |
|BIG-IQ Cloud and  |1.x   |None      |Not       |Not       |None  |None      |
|Orchestration     |      |          |applicable|vulnerable|      |          |
|F5 iWorkflow      |2.x   |None      |Not       |Not       |None  |None      |
|                  |      |          |applicable|vulnerable|      |          |
|                  |5.x   |None      |Not       |          |      |          |
|                  |      |          |applicable|Not       |      |          |
|Traffix SDC       +------+----------+----------+vulnerable|None  |None      |
|                  |4.x   |None      |Not       |          |      |          |
|                  |      |          |applicable|          |      |          |

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

Security Advisory Recommended Actions

If you are running a version listed in the Versions known to be vulnerable
column, you can eliminate this vulnerability by upgrading to a version listed
in the Fixes introduced in column. If the table lists only an older version
than what you are currently running, or does not list a non-vulnerable
version, then no upgrade candidate currently exists.


To mitigate this vulnerability, you can disable LRO by modifying the
tm.tcplargereceiveoffload database variable. To do so, perform the following

Impact of procedure: The following procedure restarts the Traffic Management
Microkernel (TMM), and you should perform the procedure only during a
maintenance window. Disabling LRO may increase CPU utilization.

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


 2. Disable LRO by typing the following command:

    modify /sys db tm.tcplargereceiveoffload value disable

 3. Restart TMM by typing the following command:

    restart /sys service tmm

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 K9502: BIG-IP hotfix and point release matrix
  o K13123: Managing BIG-IP product hotfixes (11.x - 13.x)
  o K15113: BIG-IQ hotfix matrix
  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
  o K51754851: BIG-IP system vulnerability CVE-2018-5512

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