Summary

• A vulnerability in the Secure Copy Protocol (SCP) and SFTP feature of Cisco IOS XR Software could allow an authenticated, local attacker to create or overwrite files in a system directory, which could lead to a denial of service (DoS) condition. The attacker would require valid user credentials to perform this attack.

  This vulnerability is due to a lack of proper validation of SCP and SFTP CLI input parameters. An attacker could exploit this vulnerability by authenticating to the device and issuing SCP or SFTP CLI commands with specific parameters. A successful exploit could allow the attacker to impact the functionality of the device, which could lead to a DoS condition. The device may need to be manually rebooted to recover.

  Note: This vulnerability is exploitable only when a local user invokes SCP or SFTP commands at the Cisco IOS XR CLI. A local user with administrative privileges could exploit this vulnerability remotely.

  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-iosxr-scp-dos-kb6sUUHw

  This advisory is part of the March 2024 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2024 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication.

Affected Products

• Vulnerable Products

  At the time of publication, this vulnerability affected Cisco devices if they were running a vulnerable release of Cisco IOS XR Software. This vulnerability is related to the SCP and SFTP features, which are enabled by default.

  For information about which Cisco software releases were vulnerable at the time of publication, see the Fixed Software section of this advisory. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

  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:

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

Workarounds

• There are no workarounds that address this vulnerability.

  However, because this vulnerability is exploitable only by a local user who invokes SCP or SFTP commands at the Cisco IOS XR CLI, customers can use authentication, authorization, and accounting (AAA) command authorization to block the scp and sftp CLI commands or to allow the scp and sftp commands to be used only by trusted users. For more information, see the "Enabling AAA Authorization" section of Configuring AAA Services on Cisco IOS XR Software. As noted above, this vulnerability is exploitable remotely by a user with administrative privileges.

  While this mitigation has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

Fixed Software

• 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.

  Fixed Releases

  At the time of publication, the release information in the following table was accurate. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

  The left column lists Cisco software releases, and the right column indicates whether a release was affected by the vulnerability that is described in this advisory and which release included the fix for this vulnerability.

  Cisco IOS XR Software Release	First Fixed Release
  7.9 and earlier	Migrate to a fixed release.
  7.10	Migrate to a fixed release.
  7.11	7.11.1
  24.1	24.1.1

  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-iosxr-scp-dos-kb6sUUHw

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2024-MAR-13

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