Hash: SHA256

             AUSCERT External Security Bulletin Redistribution

                iControl SOAP vulnerability CVE-2021-23026
                              25 August 2021


        AusCERT Security Bulletin Summary

Product:           BIG-IP
Publisher:         F5 Networks
Operating System:  Network Appliance
Impact/Access:     Cross-site Request Forgery -- Remote with User Interaction
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-23026  

Original Bulletin: 

- --------------------------BEGIN INCLUDED TEXT--------------------

K53854428: iControl SOAP vulnerability CVE-2021-23026

Original Publication Date: 24 Aug, 2021

Security Advisory Description

BIG-IP and BIG-IQ are vulnerable to cross-site request forgery (CSRF) attacks
through iControl SOAP.  (CVE-2021-23026)


An attacker may trick authenticated users into performing critical actions.
This vulnerability can only be exploited through the control plane and cannot
be exploited through the data plane. Exploitation can lead to complete system

Security Advisory Status

F5 Product Development has assigned ID 935433 (BIG-IP) and ID 935433-8 (BIG-IQ)
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.

Note: After a fix is introduced for a given minor branch, that fix applies to
all subsequent maintenance and point releases for that branch, and no
additional fixes for that branch will be listed in the table. For example, when
a fix is introduced in, the fix also applies to, and all
later 14.1.x releases (14.1.3.x., 14.1.4.x). For more information, refer to
K51812227: Understanding security advisory versioning. Additionally, software
versions preceding those listed in the following table have reached the End of
Technical Support (EoTS) phase of their lifecycle and are no longer evaluated
for security issues. For more information, refer to the Security hotfixes
section of K4602: Overview of the F5 security vulnerability response policy.

|            |      |Versions known|Fixes     |          |CVSSv3|Vulnerable   |
|Product     |Branch|to be         |introduced|Severity  |score^|component or |
|            |      |vulnerable^1  |in        |          |2     |feature      |
|            |16.x  |16.0.0 -      |16.1.0^3  |          |      |             |
|            |      |16.0.1        |^3|          |      |             |
|            +------+--------------+----------+          |      |             |
|            |15.x  |15.1.0        |15.1.3^3  |          |      |             |
|            |      |- 15.1.2      |          |          |      |             |
|            +------+--------------+----------+          |      |             |
|            |14.x  |14.1.0 -      |^3|          |      |             |
|BIG-IP (all |      |14.1.4        |          |          |      |             |
|modules)    +------+--------------+----------+High      |7.5   |iControl SOAP|
|            |13.x  |13.1.0 -      |^3|          |      |             |
|            |      |13.1.4        |          |          |      |             |
|            +------+--------------+----------+          |      |             |
|            |12.x  |12.1.0 -      |Will not  |          |      |             |
|            |      |12.1.6        |fix       |          |      |             |
|            +------+--------------+----------+          |      |             |
|            |11.x  |11.6.1 -      |Will not  |          |      |             |
|            |      |11.6.5        |fix       |          |      |             |
|            |8.x   |8.0.0 - 8.1.0 |None      |          |      |             |
|BIG-IQ      +------+--------------+----------+          |      |             |
|Centralized |7.x   |7.0.0 - 7.1.0 |None      |High      |7.5   |iControl SOAP|
|Management  +------+--------------+----------+          |      |             |
|            |6.x   |6.0.0 - 6.1.0 |None      |          |      |             |
|F5OS        |1.x   |None          |Not       |Not       |None  |None         |
|            |      |              |applicable|vulnerable|      |             |
|Traffix SDC |5.x   |None          |Not       |Not       |None  |None         |
|            |      |              |applicable|vulnerable|      |             |

^1F5 only evaluates software versions that have not yet reached the End of
Technical Support (EoTS) phase of their lifecycle.

^2The CVSSv3 score link takes you to a resource outside of AskF5, and it is
possible that the document may be removed without our knowledge.

^3The fixed versions resolve this issue for token based authentication, however
HTTP basic authentication may expose this issue in a web browser. See the 
Recommended actions for more details.

Recommended Actions

This attack cannot be prevented if a user has authenticated to iControl SOAP in
the web browser with basic authentication. This authentication mechanism is
uncommon and is not the same as using the login page for TMUI. F5 recommends
that users do not authenticate with basic authentication in the web browser. F5
recommends disabling basic authentication to iControl SOAP by changing the DB
variable httpd.basic_auth to disable. Also following the recommendations of
using an isolated web browser to mitigate this vulnerability. For more
information on disabling basic authentication, refer to K58092347: Disable
Basic Auth for iControl SOAP and iControl REST.

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 can use a unique and isolated web browser
when managing the BIG-IP or BIG-IQ system and restrict access to the iControl
API of the system to only trusted users.

For more information about limiting access to trusted users, refer to K17459:
Restricting access to the iControl SOAP API by source IP address.


This issue was discovered internally by F5.

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 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

- --------------------------END INCLUDED TEXT--------------------

You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.

NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:


Australian Computer Emergency Response Team
The University of Queensland
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
Comment: http://www.auscert.org.au/render.html?it=1967