Summary

• A vulnerability in the boot process of Cisco IOS XR Software could allow an authenticated, local attacker with high privileges to bypass the Cisco Secure Boot functionality and load unverified software on an affected device. To exploit this successfully, the attacker must have root-system privileges on the affected device.

  This vulnerability is due to an error in the software build process. An attacker could exploit this vulnerability by manipulating the system’s configuration options to bypass some of the integrity checks that are performed during the booting process. A successful exploit could allow the attacker to control the boot configuration, which could enable them to bypass of the requirement to run Cisco signed images or alter the security properties of the running system.

  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-xr-secure-boot-quD5g8Ap

Affected Products

• Vulnerable Products

  This vulnerability affects the following Cisco products if they are running Cisco IOS XR Release 24.2.1:

  • 8000 Series Routers
  • NCS 1010 Series Routers
  • NCS 1014 Series Routers
  • NCS 540 Series Routers that are running the NCS540L images
  • NCS 5700 Fixed Port Series Routers, excluding NCS-57C3-MOD-S and NCS-57C3-MOD-SE-S

  Note: Cisco IOS XR release 24.2.1 is the only vulnerable release.

  Determine the Software Release

  To determine whether the device is running an affected software image, use the show version command in the device CLI. If the output indicates Version 24.2.1 running on an affected product listed above, as shown in the following example, then the device is affected by this vulnerability:

  Router# show version
  Cisco IOS XR Software, Version 24.2.1
  Copyright (c) 2013-2024 by Cisco Systems, Inc.

  
  

  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 IOS XR products:

  • ASR 9000 Series Routers
  • IOS XRv 9000 Routers
  • NCS 540 Series Routers NCS540-ACC-SYS and NCS 540-24Z8Q2C-SYS
  • NCS 5500 Series Routers
  • NCS 5700 Fixed Port Series Routers NCS-57C3-MOD-S and NCS-57C3-MOD-SE-S

  Cisco has confirmed that this vulnerability does not affect the following Cisco products:

  • IOS Software
  • IOS XE Software
  • NX-OS Software

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 with service contracts that entitle them to regular software updates should obtain security fixes through their usual update channels.

  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.

  The Cisco Support and Downloads page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool.

  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

  This issue only affects Cisco IOS XR Release 24.2.1 running on the platforms that are listed in the Vulnerable Products section of this advisory. The fixed release is 24.2.11.

  The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.

Exploitation and Public Announcements

• The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.

Source

• This vulnerability was found during internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xr-secure-boot-quD5g8Ap

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2024-JUL-10

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