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             AUSCERT External Security Bulletin Redistribution

                     BIND vulnerability CVE-2019-6477
                                8 July 2020


        AusCERT Security Bulletin Summary

Product:           F5 BIG-IP products
                   F5 Enterprise Manager
                   F5 BIG-IQ
                   F5 Traffix SDC
Publisher:         F5 Networks
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-6477  

Reference:         ESB-2019.4419

Original Bulletin: 

Revision History:  July      8 2020: Vendor updated Security Advisory Status table, 
                                     adding an additional branch
                   June     19 2020: Vendor updated Security Advisory Status table
                   February 11 2020: Updatedd Security Advisory Status table
                   January  14 2020: Product table updated
                   December  5 2019: Initial Release

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K15840535:BIND vulnerability CVE-2019-6477

Security Advisory

Original Publication Date: 03 Dec, 2019

Latest   Publication Date: 08 Jul, 2020

Security Advisory Description

With pipelining enabled each incoming query on a TCP connection requires a
similar resource allocation to a query received via UDP or via TCP without
pipelining enabled. A client using a TCP-pipelined connection to a server could
consume more resources than the server has been provisioned to handle. When a
TCP connection with a large number of pipelined queries is closed, the load on
the server releasing these multiple resources can cause it to become
unresponsive, even for queries that can be answered authoritatively or from
cache. (This is most likely to be perceived as an intermittent server problem).


An attacker may be able to use TCP-pipelined queries to increase the load on
the system, causing it to become unresponsive.

Security Advisory Status

F5 Product Development has assigned ID 852445 (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.

|                   |      |Versions  |Fixes     |          |CVSSv3|Vulnerable|
|Product            |Branch|known to  |introduced|Severity  |score^|component |
|                   |      |be        |in        |          |1     |or feature|
|                   |      |vulnerable|          |          |      |          |
|                   |16.x  |None      |16.0.0    |          |      |          |
|                   +------+----------+----------+          |      |          |
|                   |15.x  |15.0.1 -  |None      |          |      |          |
|                   |      |15.1.0    |          |          |      |          |
|                   +------+----------+----------+          |      |          |
|BIG-IP (LTM, AAM,  |14.x  |14.1.1 -  |  |          |      |          |
|AFM, Analytics,    |      |14.1.2    |          |          |      |          |
|APM, ASM, DNS, FPS,+------+----------+----------+High      |7.5   |BIND      |
|GTM, Link          |13.x  |13.1.2 -  |  |          |      |          |
|Controller, PEM)   |      |13.1.3    |          |          |      |          |
|                   +------+----------+----------+          |      |          |
|                   |12.x  |12.1.5    |  |          |      |          |
|                   +------+----------+----------+          |      |          |
|                   |11.x  |11.6.5    |  |          |      |          |
|                   |      |11.5.10   |          |          |      |          |
|Enterprise Manager |3.x   |None      |Not       |Not       |None  |None      |
|                   |      |          |applicable|vulnerable|      |          |
|                   |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|      |          |

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.


If you have enabled TCP-pipelining, you can mitigate this vulnerability by
disabling TCP-pipelining by adding the appropriate statement to the named.conf 
file. To do so, perform one of the following procedures:

  o Disabling TCP-pipelining from the Configuration utility
  o Disabling TCP-pipelining by editing the named.conf file

Disabling TCP-pipelining from the Configuration utility

 1. Log in to the Configuration utility.
 2. Navigate to DNS > Zones > ZoneRunner > named Configuration.
 3. To disable server TCP-pipelining, in the named Options box, add the
    following line to the options stanza:

    keep-response-order { any; };

 4. Select Update.

Disabling TCP-pipelining by editing the named.conf file

Impact of action: This procedure restarts the named service, which may affect
the BIG-IP system responding to DNS queries.

 1. Log in to the BIG-IP command line.
 2. Navigate to /var/named/config by typing the following command:

    cd  /var/named/config

 3. Use a text editor to edit the named.conf file.

    For example:

    vi named.conf

 4. To disable server TCP-pipelining, add the following line to the options 

    keep-response-order { any; };

 5. Save the changes and exit the file.
 6. Restart the named service by typing the following command:

    tmsh restart /sys service named

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 - 15.x)
  o K15106: Managing BIG-IQ product hotfixes
  o K15113: BIG-IQ hotfix and point release 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

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