Summary

• A vulnerability in a legacy capability that allowed for the preloading of VPN clients and plug-ins and that has been available in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an authenticated, local attacker to execute arbitrary code with root-level privileges. Administrator-level privileges are required to exploit this vulnerability.

  This vulnerability is due to improper validation of a file when it is read from system flash memory. An attacker could exploit this vulnerability by copying a crafted file to the disk0: file system of an affected device. A successful exploit could allow the attacker to execute arbitrary code on the affected device after the next reload of the device, which could alter system behavior. Because the injected code could persist across device reboots, Cisco has raised the Security Impact Rating (SIR) of this advisory from Medium to High.

  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-asaftd-persist-rce-FLsNXF4h

  For more information on the vulnerability that is described in this advisory, see Cisco Event Response: Attacks Against Cisco Firewall Platforms.

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco products if they are running a vulnerable release of Cisco ASA Software or FTD Software. No specific configuration is required.

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

  Products Confirmed Not Vulnerable

  Only products and services 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.

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.

  Cisco ASA, FMC, and FTD Software

  To help customers determine their exposure to vulnerabilities in Cisco ASA, FMC, and FTD Software, Cisco provides the Cisco Software Checker. This tool identifies any Cisco security advisories that impact a specific software release and the earliest release that fixes the vulnerabilities that are described in each advisory (“First Fixed”). If applicable, the tool also returns the earliest release that fixes all the vulnerabilities that are described in all the advisories that the Software Checker identifies (“Combined First Fixed”).

  To use the tool, go to the Cisco Software Checker page and follow the instructions. Alternatively, use the following form to search for vulnerabilities that affect a specific software release. To use the form, follow these steps:

  1. Choose which advisories the tool will search—all advisories, only advisories with a Critical or High Security Impact Rating (SIR), or only this advisory.
  2. Choose the appropriate software.
  3. Choose the appropriate platform.
  4. Enter a release number—for example, 9.16.2.11 for Cisco ASA Software or 6.6.7 for Cisco FTD Software.
  5. Click Check.

  Only this advisory All Critical and High advisories All advisories Cisco ASA Software Cisco FMC Software Cisco FTD Software Any Platform 3000 Series Industrial Security Appliances (ISA) ASA 5500-X Series Firewalls ASA Service Module Adaptive Security Virtual Appliance (ASAv) Firepower 1000 Series Firepower 2100 Series Firepower 4100 Series Firepower 9000 Series Secure Firewall 3100 Series

   

  For instructions on upgrading an FTD device, see Cisco Firepower Management Center Upgrade Guide.

   

  Additional Resources

  For help determining the best Cisco ASA, FMC, or FTD Software release, see the following Recommended Releases documents. If a security advisory recommends a later release, Cisco recommends following the advisory guidance.

  Cisco ASA Compatibility
  Cisco Secure Firewall ASA Upgrade Guide
  Cisco Secure Firewall Threat Defense Compatibility Guide

Recommendations

• After upgrading to a release with the fix for this vulnerability, Cisco recommends that customers check the output of the dir disk0: command on the device CLI for any new .zip files that were not showing up before the upgrade.

  If a new file named client_bundle_install.zip or any other unusual .zip file appears after the upgrade, copy that file off the device using the copy command and contact psirt@cisco.com referencing CVE-2024-20359. Include the outputs of the dir disk0: and show version commands from the device and the .zip file that was extracted from the device.

Exploitation and Public Announcements

• Cisco has confirmed that this vulnerability has been exploited. Cisco strongly recommends that customers upgrade to fixed software to resolve this vulnerability. Customers are also strongly encouraged to monitor system logs for indicators of undocumented configuration changes, unscheduled reboots, and any anomalous credential activity.

Source

• Cisco would like to thank the following organizations for supporting this investigation:

  • Australian Signals Directorate's Australian Cyber Security Centre
  • Canadian Centre for Cyber Security, a part of the Communications Security Establishment
  • The UK's National Cyber Security Centre (NCSC)
  • U.S. Cybersecurity & Infrastructure Security Agency (CISA)

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-persist-rce-FLsNXF4h

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2024-APR-24

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