Summary

• A vulnerability in the CLI of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, local attacker to execute arbitrary commands on the underlying operating system (OS) of an affected device.

  The vulnerability is due to insufficient input validation of commands that are supplied by the user. An attacker could exploit this vulnerability by authenticating to a device and submitting crafted input for specific commands. A successful exploit could allow the attacker to execute commands on the underlying OS with root privileges. To exploit this vulnerability, an attacker must have valid administrator-level credentials.

  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-asa-ftd-cmd-inj-SELprvG

Affected Products

• Vulnerable Products

  At the time of publication, this vulnerability affected the following Cisco products:

  • ASA Software releases 9.13 through the first fixed release
  • FTD Software releases 6.5 through the first fixed release

  For information about which Cisco software releases are vulnerable, 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 Cisco Firepower Management Center (FMC) Software.

Details

• Cisco FTD Software has two modes of deployment: native mode and multi-instance (MI) mode.

  In native mode, administrators always have access to the underlying root shell (called Expert Mode). Therefore, this vulnerability does not affect Cisco FTD Software deployments that are in native mode.

  In MI mode, Expert Mode must be manually configured. Therefore, a malicious administrator who has not been granted access to the underlying root shell could exploit this vulnerability to bypass that restriction.

  For Cisco ASA Software, there is no legitimate way to access the underlying root shell. Therefore, all Cisco ASA Software deployments are affected by this vulnerability.

Workarounds

• There are no workarounds that address this vulnerability.

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(s) 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 described in this advisory and which release included the fix for this vulnerability.

  ASA Software

  Cisco ASA Software Release	First Fixed Release for This Vulnerability
  Earlier than 9.131	Not vulnerable.
  9.13	9.13.1.21
  9.14	9.14.2.13
  9.15	9.15.1.10

  1. Cisco ASA Software releases 9.7 and earlier, as well as Release 9.10, have reached end of software maintenance. Customers are advised to migrate to a supported release that includes the fix for this vulnerability.

  FTD Software

  Cisco FTD Software Release	First Fixed Release for This Vulnerability
  Earlier than 6.51	Not vulnerable.
  6.5.0	Migrate to a fixed release.
  6.6.0	6.6.42
  6.7.0	6.7.0.2

  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.

  2. The First Fixed Release for the 6.6.0 code train was 6.6.3; however, due to upgrade issues associated with CSCvx86231 the recommended release is 6.6.4.

  To upgrade to a fixed release of Cisco FTD Software, do one of the following:

  • For devices that are managed by using Cisco Firepower Management Center (FMC), use the FMC interface to install the upgrade. After installation is complete, reapply the access control policy.
  • For devices that are managed by using Cisco Firepower Device Manager (FDM), use the FDM interface to install the upgrade. After installation is complete, reapply the access control policy.

Exploitation and Public Announcements

• 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.

Source

• This vulnerability was found by Ilkin Gasimov of Cisco during internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-cmd-inj-SELprvG

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2021-APR-28

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