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===========================================================================
             AUSCERT External Security Bulletin Redistribution

                               ESB-2021.0499
                BIG-IP SSL/TLS vulnerability CVE-2021-22981
                             11 February 2021

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           BIG-IP products
Publisher:         F5 Networks
Operating System:  Network Appliance
Impact/Access:     Access Confidential Data -- Unknown/Unspecified
                   Reduced Security         -- Unknown/Unspecified
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-22981  

Original Bulletin: 
   https://support.f5.com/csp/article/K09121542

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K09121542: BIG-IP SSL/TLS vulnerability CVE-2021-22981

Original Publication Date: 11 Feb, 2021

Security Advisory Description

The original TLS protocol includes a weakness in the master secret negotiation
that is mitigated by the Extended Master Secret (EMS) extension defined in RFC
7627. TLS connections that do not use EMS are vulnerable to man-in-the-middle
attacks during renegotiation. (CVE-2021-22981).

Impact

This vulnerability impacts the BIG-IP data plane. Attackers may set up a second
Transport Layer Security (TLS) session with the same master secrets to carry
out man-in-the-middle attacks (Triple Handshake attack) during TLS
renegotiation.

For more information on BIG-IP support for RFC 7627: Transport Layer Security
(TLS) Session Hash and Extended Master Secret Extension, refer to K66202244:
Support for RFC 7627 extended master secret extension.

Security Advisory Status

F5 Product Development has assigned ID 563491 (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      |Not       |          |      |          |
|                   |      |          |applicable|          |      |          |
|                   +------+----------+----------+          |      |          |
|                   |15.x  |None      |Not       |          |      |          |
|BIG-IP (LTM, AAM,  |      |          |applicable|          |      |          |
|Advanced WAF, AFM, +------+----------+----------+          |      |          |
|Analytics, APM,    |14.x  |None      |Not       |          |      |          |
|ASM, DDHD, DNS,    |      |          |applicable|Medium    |4.2   |SSL       |
|FPS, GTM, Link     +------+----------+----------+          |      |profiles  |
|Controller, PEM,   |13.x  |None      |13.0.0    |          |      |          |
|SSLO)              +------+----------+----------+          |      |          |
|                   |12.x  |12.1.0 -  |None      |          |      |          |
|                   |      |12.1.5    |          |          |      |          |
|                   +------+----------+----------+          |      |          |
|                   |11.x  |11.6.1 -  |None      |          |      |          |
|                   |      |11.6.5    |          |          |      |          |
+-------------------+------+----------+----------+----------+------+----------+
|                   |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|      |          |
+-------------------+------+----------+----------+----------+------+----------+

^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

None

Supplemental Information

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 - 16.x)
  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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