ESB-2018.0602 - [Appliance] F5 BIG-IP Products: Denial of service - Remote/unauthenticated 2018-03-02

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             AUSCERT External Security Bulletin Redistribution

                K33211839: TMM vulnerability CVE-2018-5500
                               2 March 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-2018-5500  

Original Bulletin:

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K33211839: TMM vulnerability CVE-2018-5500

Security Advisory

Original Publication Date: Mar 01, 2018

Security Advisory Description

Every Multipath TCP (MCTCP) connection established leaks a small amount of
memory. Virtual server using TCP profile with Multipath TCP (MCTCP) feature
enabled will be affected by this issue. (CVE-2018-5500)


Over a period of time, the memory leak may lead to memory exhaustion on the
system. The standard configuration of the default TCP profile named
mptcp-mobile-optimized has MPTCP feature is enabled.

Security Advisory Status

F5 Product Development has assigned ID 671638 (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.

|                  |      |Versions  |Fixes     |          |CVSSv3|Vulnerable |
|Product           |Branch|known to  |introduced|Severity  |score^|component  |
|                  |      |be        |in        |          |1     |or feature |
|                  |      |vulnerable|          |          |      |           |
|                  |13.x  |13.0.0    |13.1.0    |          |      |TMM.       |
|BIG-IP (LTM, AAM, |      |          |          |          |      |Virtual    |
|AFM, Analytics,   +------+----------+----------+          |      |server     |
|APM, ASM, DNS,    |      |12.1.0 -  |          |          |      |using TCP  |
|Edge Gateway,     |12.x  |12.1.3    |  |Medium    |5.9   |profile    |
|GTM, Link         |      |          |          |          |      |with       |
|Controller, PEM,  +------+----------+----------+          |      |Multipath  |
|WebAccelerator,   |      |11.6.1 -  |          |          |      |TCP        |
|WebSafe)          |11.x  |11.6.2    |11.6.3    |          |      |enabled.   |
|                  |      |          |          |          |      |           |
|ARX               |6.x   |None      |Not       |Not       |None  |None       |
|                  |      |          |applicable|vulnerable|      |           |
|Enterprise Manager|3.x   |None      |Not       |Not       |None  |None       |
|                  |      |          |applicable|vulnerable|      |           |
|                  |5.x   |None      |Not       |          |      |           |
|BIG-IQ Centralized|      |          |applicable|Not       |      |           |
|Management        +------+----------+----------+vulnerable|None  |None       |
|                  |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|      |           |
|LineRate          |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.

Note: For details about how Security Advisory articles are versioned, and what
versions are listed in the table, refer to K51812227: Understanding Security
Advisory versioning.


If the MPTCP feature is required in your environment, there is no mitigation
method available.

If the MPTCP feature is not required in your environment, you can prevent this
issue by disabling MPTCP on the TCP profile used by the affected virtual server

To mitigate this vulnerability, you can disable the MPTCP feature on the TCP
profile. To do so, perform one of the following procedures:

Impact of action: Disabling the MPTCP from the affected profile will only
affect the incoming new connection. The existing connections that are still
established will continue to have MPTCP enabled until the connection reaches
its timeout value.

Using the Configuration utility

 1. Log in to the Configuration utility.
 2. Navigate to Local Traffic > Profiles > Protocol, and select the affected
    profile name.
 3. Navigate to the Multipath TCP (MPTCP) section, click the custom box on the
 4. Clear the box for Multipath TCP.
 5. Click Update.

Using the Traffic Management Shell (tmsh) utility

 1. Log in to the tmsh utility by typing the following command:


 2. Disable MPTCP by using the following command syntax:

    modify /ltm profile tcp <Profile-Name> mptcp disabled

    For example:

    modify /ltm profile tcp my_profile1 mptcp disabled

 3. Save the configuration changes by typing the following command:

    save /sys config

 4. Exit tmsh by typing the following command:


Supplemental Information

  o K9970: Subscribing to email notifications regarding F5 products
  o K9957: Creating a custom RSS feed to view new and updated documents
  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 K13123: Managing BIG-IP product hotfixes (11.x - 13.x)
  o K9502: BIG-IP hotfix and point release matrix

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