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             AUSCERT External Security Bulletin Redistribution

                               ESB-2020.4498
         BIG-IP Configuration utility vulnerability CVE-2020-27715
                             18 December 2020

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

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

Product:           BIG-IP
Publisher:         F5 Networks
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-27715  

Original Bulletin: 
   https://support.f5.com/csp/article/K25691186

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K25691186: BIG-IP Configuration utility vulnerability CVE-2020-27715

Original Publication Date: 17 Dec, 2020

Security Advisory Description

Crafted TLS request to the BIG-IP management interface via port 443 can cause
high (~100%) CPU utilization by the httpd daemon. (CVE-2020-27715)

Impact

Unable to access the affected BIG-IP system's Configuration utility.

Security Advisory Status

F5 Product Development has assigned ID 851089 (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 or |
|                |      |be        |in        |          |1     |feature      |
|                |      |vulnerable|          |          |      |             |
+----------------+------+----------+----------+----------+------+-------------+
|                |16.x  |None      |16.0.0    |          |      |             |
|                +------+----------+----------+          |      |             |
|                |15.x  |15.0.0 -  |15.1.1    |          |      |             |
|                |      |15.1.0    |          |          |      |             |
|                +------+----------+----------+          |      |             |
|BIG-IP (LTM,    |14.x  |14.1.0 -  |14.1.3.1  |          |      |             |
|AAM, AFM,       |      |14.1.3    |          |          |      |             |
|Analytics, APM, +------+----------+----------+High      |7.5   |Configuration|
|ASM, DNS, FPS,  |13.x  |None      |Not       |          |      |utility      |
|GTM, Link       |      |          |applicable|          |      |             |
|Controller, PEM)+------+----------+----------+          |      |             |
|                |12.x  |None      |Not       |          |      |             |
|                |      |          |applicable|          |      |             |
|                +------+----------+----------+          |      |             |
|                |11.x  |None      |Not       |          |      |             |
|                |      |          |applicable|          |      |             |
+----------------+------+----------+----------+----------+------+-------------+
|                |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

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

If the BIG-IP configuration utility is no longer accessible, you can recover
the access using the TMOS Shell (tmsh) access with administrator credentials to
restart the httpd service. To restart httpd service using tmsh access, enter
the following command: 
restart /sys service httpd

Impact of action: Performing the following procedure should not have a negative
impact on your system because the Configuration utility is no longer
accessible.

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 K48955220: Installing an OPSWAT Endpoint Security update on BIG-IP APM
    systems (11.4.x and later)
  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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