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             AUSCERT External Security Bulletin Redistribution

    K95343321: Linux kernel vulnerability (SegmentSmack) CVE-2018-5390
                               16 April 2019


        AusCERT Security Bulletin Summary

Product:           F5 products
Publisher:         F5 Networks
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Mitigation
CVE Names:         CVE-2018-5390  

Reference:         ESB-2018.2401

Original Bulletin: 

Revision History:  April    16 2019: Updated with latest publication
                   April     4 2019: Updated with latest publication
                   March    27 2019: Updated with latest publication
                   March    22 2019: Updated product table
                   March    13 2019: Updated product table
                   December 14 2018: Updated product table
                   August   21 2018: Initial Release

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K95343321:Linux kernel vulnerability CVE-2018-5390

Security Advisory

Original Publication Date: 07 Aug, 2018

Latest   Publication Date: 16 Apr, 2019

Security Advisory Description

Linux kernel versions 4.9+ can be forced to make very expensive calls to
tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() for every incoming packet
which can lead to a denial of service. (CVE-2018-5390 also known as


For products with vulnerable versions, this vulnerability allows a remote
attacker to disrupt service. This vulnerability affects only the BIG-IP
management port.

For products with None in the Versions known to be vulnerable column, there is
no impact.

Security Advisory Status

F5 Product Development has assigned IDs 739970 (BIG-IP), and ID CPF-24972 and
CPF-24973 (Traffix SDC) to these vulnerabilities.

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  |14.0.0    |14.1.0    |          |      |           |
|                  +------+----------+----------+          |      |           |
|BIG-IP (LTM, AAM, |13.x  |13.0.0 -  |  |          |      |           |
|AFM, Analytics,   |      |13.1.1    |          |          |      |           |
|APM, ASM, DNS,    +------+----------+----------+          |      |Linux      |
|Edge Gateway, FPS,|12.x  |12.1.0 -  |  |High      |7.5   |kernel     |
|GTM, Link         |      |12.1.4    |          |          |      |(management|
|Controller, PEM,  +------+----------+----------+          |      |port)      |
|WebAccelerator)   |      |11.6.1 -  |          |          |      |           |
|                  |11.x  |11.6.3    |11.6.4    |          |      |           |
|                  |      |11.5.1 -  |11.5.9    |          |      |           |
|                  |      |11.5.8    |          |          |      |           |
|ARX               |6.x   |None      |Not       |Not       |None  |None       |
|                  |      |          |applicable|vulnerable|      |           |
|Enterprise Manager|3.x   |None      |Not       |Not       |None  |None       |
|                  |      |          |applicable|vulnerable|      |           |
|                  |6.x   |None      |Not       |          |      |           |
|BIG-IQ Centralized|      |          |applicable|Not       |      |           |
|Management        +------+----------+----------+vulnerable|None  |None       |
|                  |5.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   |5.0.0 -   |None      |          |      |           |
|Traffix SDC       |      |5.1.0     |          |High      |7.5   |Linux      |
|                  +------+----------+----------+          |      |kernel     |
|                  |4.x   |4.4.0     |None      |          |      |           |

^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.


To mitigate this vulnerability, you should permit management access to F5
products only over a secure network and restrict command line access for
affected systems to trusted users. For more information, refer to K13309:
Restricting access to the Configuration utility by source IP address (11.x -
14.x) and K13092: Overview of securing access to the BIG-IP system.

Additionally, the BIG-IP standard virtual server mitigates this vulnerability
for back-end servers using the full proxy architecture. The BIG-IP forwarding
virtual server and its variants do not provide that mitigation for back-end

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 K9970: Subscribing to email notifications regarding F5 products
  o K9957: Creating a custom RSS feed to view new and updated documents
  o K74374841: Linux kernel vulnerability CVE-2018-5391
  o K8082: Overview of TCP connection setup for BIG-IP LTM virtual server types

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