Cisco Security Advisory
Cisco Firepower Management Center Software Common Access Card Authentication Bypass Vulnerability
A vulnerability in the Common Access Card (CAC) authentication feature of Cisco Firepower Management Center (FMC) Software could allow an unauthenticated, remote attacker to bypass authentication and access the FMC system. The attacker must have a valid CAC to initiate the access attempt.
The vulnerability is due to incorrect session invalidation during CAC authentication. An attacker could exploit this vulnerability by performing a CAC-based authentication attempt to an affected system. A successful exploit could allow the attacker to access an affected system with the privileges of a CAC-authenticated user who is currently logged in.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
This advisory is available at the following link:
This advisory is part of the October 2020 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication, which includes 17 Cisco Security Advisories that describe 17 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: October 2020 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication.
This vulnerability affects Cisco FMC Software if it is running software release 6.6.0 or 126.96.36.199 and has CAC-based authentication configured.
For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.
Determine Whether CAC Authentication Is Enabled
The response to a login attempt in the FMC GUI indicates whether CAC authentication is enabled:
- CAC authentication is enabled if the user is prompted with Press Log In to use the inserted CAC for authentication.
- CAC authentication is not enabled if the user is prompted with username and password fields.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect the following Cisco products:
- Adaptive Security Appliance (ASA) Software
- Firepower Device Manager (FDM) Software
- Firepower Threat Defense (FTD) Software
There are no workarounds that address this vulnerability.
Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
Additionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page, to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
In the following table(s), the left column lists Cisco software releases. The center column indicates whether a release is affected by the vulnerability described in this advisory and the first release that includes the fix for this vulnerability. The right column indicates whether a release is affected by any of the vulnerabilities described in this bundle and which release includes fixes for those vulnerabilities.
Cisco FMC Software
Cisco FMC Software Release First Fixed Release for This Vulnerability First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories Earlier than 6.2.21 Not vulnerable. Migrate to a fixed release. 6.2.2 Not vulnerable. Migrate to a fixed release. 6.2.3 Not vulnerable. Migrate to a fixed release. 6.3.0 Not vulnerable. Migrate to a fixed release. 6.4.0 Not vulnerable. Migrate to a fixed release. 6.5.0 Not vulnerable. Migrate to a fixed release. 6.6.0 6.6.1 6.6.1
1. Cisco FMC and FTD Software releases 6.0.1 and earlier, as well as releases 6.2.0 and 6.2.1, have reached end of software maintenance. Customers are advised to migrate to a supported release that includes the fix for this vulnerability.
The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
This vulnerability was found by John Maroney during the resolution of a Cisco TAC support case.
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
Version Description Section Status Date 1.0 Initial public release. - Final 2020-OCT-21
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