Cisco FXOS Software for Firepower 4100/9300 Series Appliances Secure Boot Bypass Vulnerability

Summary

A vulnerability in the secure boot process of Cisco FXOS Software could allow an authenticated, local attacker to bypass the secure boot mechanisms.

The vulnerability is due to insufficient protections of the secure boot process. An attacker could exploit this vulnerability by injecting code into a specific file that is then referenced during the device boot process. A successful exploit could allow the attacker to break the chain of trust and inject code into the boot process of the device which would be executed at each boot and maintain persistence across reboots.

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:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fxos-sbbp-XTuPkYTn

Affected Products

Vulnerable Products
This vulnerability affects Cisco FXOS Software releases when running on the following platforms:

Firepower 4100 Series Appliances

Firepower 9300 Series Appliances

For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.

For the Firepower 1000 Series Appliances and Firepower 2100 Series Appliances, see the following advisory:

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-fxos-sbbyp-KqP6NgrE
Products Confirmed Not Vulnerable

Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.

Workarounds

There are no workarounds that address this vulnerability.

Fixed Software

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:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.html

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.

Fixed Releases