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             AUSCERT External Security Bulletin Redistribution

                      TMM vulnerability CVE-2019-6603
                               28 March 2019


        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-2019-6603  

Original Bulletin: 

Revision History:  March 28 2019: Added advisory update
                   March 26 2019: Added advisory update
                   March 22 2019: Initial Release

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K14632915:TMM vulnerability CVE-2019-6603

Security Advisory

Original Publication Date: 22 Mar, 2019

Latest   Publication Date: 28 Mar, 2019

Security Advisory Description

Malformed TCP packets sent to a self IP address or a FastL4 virtual server may
cause an interruption of service. The control plane is not exposed to this
issue. This issue impacts the data plane virtual servers and self IPs. (


This vulnerability allows remote disruption of service.

Security Advisory Status

F5 Product Development has assigned ID 714181 (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 or  |
|               |      |be        |in        |          |1     |feature       |
|               |      |vulnerable|          |          |      |              |
|               |14.x  |None      |14.0.0    |          |      |              |
|BIG-IP (LTM,   +------+----------+----------+          |      |TMM when      |
|AAM, AFM,      |13.x  |13.0.0 -  |13.1.0    |          |      |processing    |
|Analytics, APM,|      |13.0.1    |          |          |      |connections   |
|ASM, DNS, Edge +------+----------+----------+          |      |for a self IP |
|Gateway, FPS,  |12.x  |12.1.0 -  |12.1.4    |High      |7.5   |address, or a |
|GTM, Link      |      |12.1.3    |          |          |      |virtual server|
|Controller,    +------+----------+----------+          |      |configured    |
|PEM,           |      |11.6.0 -  |          |          |      |with a FastL4 |
|WebAccelerator)|11.x  |11.6.3    |11.6.4    |          |      |profile.      |
|               |      |11.5.1 -  |11.5.9    |          |      |              |
|               |      |11.5.8    |          |          |      |              |
|ARX            |6.x   |None      |Not       |Not       |None  |None          |
|               |      |          |applicable|vulnerable|      |              |
|Enterprise     |3.x   |None      |Not       |Not       |None  |None          |
|Manager        |      |          |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   |      |          |Not       |Not       |      |              |
|and            |1.x   |None      |applicable|vulnerable|None  |None          |
|Orchestration  |      |          |          |          |      |              |
|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|          |      |              |

^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.

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.


Mitigation for self IP addresses

To mitigate this issue for self IP addresses, you can use the port lockdown
feature to disallow unneeded ports on all self IP addresses. For more
information, refer to K13250: Overview of port lockdown behavior (10.x - 11.x)
or K17333: Overview of port lockdown behavior (12.x - 14.x).

Mitigation for FastL4 virtual servers

There is no mitigation for non-Virtual Edition (VE) systems.

For BIG-IP VE systems that have been configured with TCP Segmentation Offload
(TSO) disabled, you can mitigate this vulnerability by enabling TSO. You can
enable TSO by setting the value of the tm.tcpsegmentationoffload BigDB key to
 enable, and restarting the Traffic Management Microkernel (TMM). To do so,
perform the following procedure:

Note: TSO is enabled by default. This mitigation is only applicable if you have
manually disabled TSO on the BIG-IP VE system.

Impact of action: Because TSO enabled is the default value for BIG-IP systems,
performing the following procedure should not have a negative impact on your
system. However, if you have disabled TSO in your environment, the impact of
the suggested mitigation depends on the specific environment. F5 recommends
testing any such changes during a maintenance window with consideration to the
possible impact on your specific environment. Additionally, restarting TMM
temporarily interrupts traffic processing.

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


 2. Enable TSO by typing the following command:

    modify sys db tm.tcpsegmentationoffload value enable

 3. Restart TMM by typing the following command

    restart /sys service tmm

Supplemental Information

o K15609: Overview of TCP Segmentation Offload and Large Receive Offload
  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

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