-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

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

                               ESB-2020.2932
                BIG-IP self IP vulnerability CVE-2020-5923
                              26 August 2020

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

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

Product:           BIG-IP products
                   BIG-IQ products
Publisher:         F5 Networks
Operating System:  Network Appliance
Impact/Access:     Unauthorised Access -- Unknown/Unspecified
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-5923  

Original Bulletin: 
   https://support.f5.com/csp/article/K05975972

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

K05975972: BIG-IP self IP vulnerability CVE-2020-5923

Security Advisory

Original Publication Date: 26 Aug, 2020

Security Advisory Description

Self-IP port-lockdown bypass by way of IPv6 link-local addresses. (
CVE-2020-5923)

Impact

Port lockdowns may be bypassable on accessible self IP addresses on an ipv6
link-local address.

Security Advisory Status

F5 Product Development has assigned ID 832885 (BIG-IP) and ID 838697 (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.

+-------------------+------+----------+----------+----------+------+----------+
|                   |      |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  |15.0.0 -  |15.1.0.5  |          |      |          |
|                   |      |15.1.0    |          |          |      |          |
|                   +------+----------+----------+          |      |          |
|BIG-IP (LTM, AAM,  |14.x  |14.0.0 -  |14.1.2.7  |          |      |          |
|AFM, Analytics,    |      |14.1.2    |          |          |      |          |
|APM, ASM, DNS, FPS,+------+----------+----------+Medium    |5.4   |VLAN/     |
|GTM, Link          |13.x  |13.1.0 -  |13.1.3.4  |          |      |Self-IP   |
|Controller, PEM)   |      |13.1.3    |          |          |      |          |
|                   +------+----------+----------+          |      |          |
|                   |12.x  |12.1.0 -  |12.1.5.2  |          |      |          |
|                   |      |12.1.5    |          |          |      |          |
|                   +------+----------+----------+          |      |          |
|                   |11.x  |11.5.2 -  |11.6.5.2  |          |      |          |
|                   |      |11.6.5    |          |          |      |          |
+-------------------+------+----------+----------+----------+------+----------+
|                   |7.x   |7.0.0     |None      |          |      |          |
|                   +------+----------+----------+          |      |          |
|BIG-IQ Centralized |6.x   |6.0.0 -   |None      |Medium    |5.4   |VLAN/     |
|Management         |      |6.1.0     |          |          |      |Self-IP   |
|                   +------+----------+----------+          |      |          |
|                   |5.x   |5.4.0     |None      |          |      |          |
+-------------------+------+----------+----------+----------+------+----------+
|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

You can use a packet filter to block link-local IPv6 addresses and ports. As
noted below, treating the default allow-list as the list of allowed services
for the link-local addresses and managing the allowed services for the
configured self-IP addresses individually is also a possible workaround.

BIG-IP 

  o Ensure that self-IP addresses are accessible from only trusted networks
    using either the BIG-IP packet filter, BIG-IP AFM, or an external firewall.
  o Configure only necessary ports by way of the port lockdown
    settings. Consider required ports as described in the following article:
       K17333: Overview of port lockdown behavior (12.x - 16.x)
  o Configure the sshd / httpd allow list from expected IPv6 traffic sources
    only:
       K13309: Restricting access to the Configuration utility by source IP
        address (11.x - 16.x)
       K5380: Specifying allowable IP ranges for SSH access

BIG-IQ

  o Configure the sshd / httpd allow list from expected IPv6 traffic sources.
       K13309: Restricting access to the Configuration utility by source IP
        address (11.x - 16.x)
       K5380: Specifying allowable IP ranges for SSH access
  o Configure only the specific ports needed by the BIG-IQ deployment ports by
    way of the port lockdown settings.
       K15612: Connectivity requirements for the BIG-IQ system
       K39403510: Managing the port lockdown configuration on the BIG-IQ
        system
  o You can use an external packet filtering device to secure access to the
    BIG-IQ self IP address.
       K13092: Overview of securing access to the BIG-IP system.

- --------------------------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:

        https://www.auscert.org.au/bulletins/

===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
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.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967
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=q/K1
-----END PGP SIGNATURE-----