CVE-2020-5940

K43310520: BIG-IP TMUI vulnerability CVE-2020-5940

Original Publication Date: Nov 03, 2020

Security Advisory Description

A stored cross-site scripting (XSS) vulnerability exists in an undisclosed page of the BIG-IP Traffic Management User Interface (TMUI), also known as the BIG-IP Configuration utility. (CVE-2020-5940)

Impact

An authenticated attacker may be able to store JavaScript, which is executed when another authenticated user accesses the Configuration utility. If the victim is an administrator user with Advanced Shell (bash) access, an attacker can use Remote Code Execution to leverage a successful exploit of this vulnerability into a complete compromise of the BIG-IP system. All authenticated users can store this attack, regardless of role.

Security Advisory Status

F5 Product Development has assigned ID 814953 (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 F5’s security advisory below. For more information about security advisory versioning, refer to K51812227: Understanding security advisory versioning.

Affected and fixed versions: F5 maintains the authoritative version matrix for this advisory, and it changes over time. For the current list of affected and fixed versions, see F5’s security advisory K43310520.

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 can disable TCP Segmentation Offload (TSO). You can do so by setting the value of the tm.tcpsegmentationoffload BigDB key to disable and restarting TMM. To do so, perform the following procedure:refer to K13309: Restricting access to the Configuration utility by source IP address (11.x – 16.x) and K13092: Overview of securing access to the BIG-IP system.