Summary

• Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass the configured policies on an affected system.

  This vulnerability is due to a flaw in the FTP module of the Snort detection engine. An attacker could exploit this vulnerability by sending crafted FTP traffic through an affected device. A successful exploit could allow the attacker to bypass FTP inspection and deliver a malicious payload.

  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-snort-ftd-zXYtnjOM

  This advisory is part of the November 2023 release of the Cisco ASA, FTD, and FMC Security Advisory Bundled publication. For a complete list of the advisories and links to them, see Cisco Event Response: November 2023 Semiannual Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication.

Affected Products

• Vulnerable Products

  For information about which products were vulnerable at the time of publication, see the following sections.

  Impact to Open Source Snort

  At the time of publication, this vulnerability affected Open Source Snort 2 and Open Source Snort 3.

  For information about which Snort releases are vulnerable, see the Fixed Software section of this advisory. For more information on Snort, see the Snort website.

  Impact to Cisco FirePOWER Services and Firepower Threat Defense Products

  At the time of publication, this vulnerability affected the following Cisco products if they were running a vulnerable release of Cisco software:

  • FirePOWER Services - All platforms
  • Firepower Threat Defense (FTD) Software - All platforms

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

  Impact to Cisco IOS XE Products

  At the time of publication, this vulnerability affected the following Cisco products if they were running a release earlier than the first fixed release of Cisco Unified Threat Defense (UTD) Snort Intrusion Prevention System (IPS) Engine for Cisco IOS XE Software or Cisco UTD Engine for Cisco IOS XE SD-WAN Software:

  • 1000 Series Integrated Services Routers (ISRs)
  • 4000 Series Integrated Services Routers (ISRs)
  • Catalyst 8000V Edge Software
  • Catalyst 8200 Series Edge Platforms
  • Catalyst 8300 Series Edge Platforms
  • Catalyst 8500L Series Edge Platform
  • Cloud Services Routers 1000V Series
  • Integrated Services Virtual Router (ISRv)

  Note: UTD is not installed on these devices by default. If the UTD file is not installed, the device is not vulnerable.

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

  Determine Whether UTD Is Enabled

  To determine whether UTD is enabled on a device, issue the show utd engine standard status command and check for a Yes under Running. If there is no output, the device is not affected. The following output example shows a device that has UTD enabled:

  Router# show utd engine standard status 
  Engine version       : 1.0.19_SV2.9.16.1_XE17.3
  Profile              : Cloud-Low
  System memory        :
               Usage  : 6.00 %
               Status : Green
  Number of engines    : 1

  
  

  Engine        Running    Health     Reason    
  ===========================================
  Engine(#1):   Yes        Green      None
  =======================================================
  
  .
  .
  .

  Impact to Cisco Meraki Products

  At the time of publication, this vulnerability affected the following Cisco products if they were running a vulnerable release of Cisco software:

  • Meraki MX64 and MX64W Appliances
  • Meraki MX65 and MX65W Appliances
  • Meraki MX67, MX67C and MX67W Appliances
  • Meraki MX68, MX68W and MX68WC Appliances
  • Meraki MX75 Appliances
  • Meraki MX84 Appliances
  • Meraki MX85 Appliances
  • Meraki MX95 Appliances
  • Meraki MX100 Appliances
  • Meraki MX105 Appliances
  • Meraki MX250 Appliances
  • Meraki MX400 Appliances
  • Meraki MX450 Appliances
  • Meraki MX600 Appliances

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

  Impact to Other Cisco Products

  At the time of publication, this vulnerability affected the following Cisco products if they were running a vulnerable release of Cisco software:

  • Cyber Vision
  • Umbrella Secure Internet Gateway (SIG)

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

  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:

  • Adaptive Security Appliance (ASA) Software
  • Catalyst 8500 Series Edge Platforms
  • Firepower Management Center (FMC) Software
  • Meraki vMX
  • Meraki Z1 Appliances
  • Meraki Z3 Series Appliances

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

  For information on which Snort and Cisco software releases were vulnerable at the time of publication, see the sections below.

  Cisco Firepower and FTD Software

  The Cisco Software Checker does not discriminate between Cisco FTD devices that are configured with Snort 2 and Snort 3. For configuration-dependent fixed and vulnerable information, see the table below. For configuration-independent fixed and vulnerable information, see the Cisco Software Checker.

  Configuration-Dependent Information

  In the following table(s), the left column lists Cisco software releases. The middle column indicates whether a Cisco FTD Software release that is configured for Snort 2 is affected by the vulnerability that is described in this advisory and the first release that includes the fix for that vulnerability. The right column indicates whether an Cisco FTD Software release that is configured for Snort 3 is affected by the vulnerability that is described in this advisory and the first release that includes the fix for that vulnerability.

  Customers are advised to upgrade to an appropriate fixed software release as indicated in this section.

  Cisco FTD Software Release	CSCwd83613	CSCwb69096
  6.3 and earlier	Migrate to a fixed release.	Not affected.
  6.4	6.4.0.17	Not affected.
  6.5	Migrate to a fixed release.	Not affected.
  6.6	Migrate to a fixed release.	Not affected.
  6.7	Migrate to a fixed release.	Migrate to a fixed release.1
  7.0	7.0.6	7.0.5
  7.1	Migrate to a fixed release.	7.1.0.3
  7.2	7.2.4	7.2.1
  7.3	7.3.1.2 (Mar 2024)	Not vulnerable.

  1. The Snort 3 configuration option is only available for devices managed by Cisco FDM in Cisco FTD Release 6.7.

  
  

  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 advisoryAll Critical and High advisoriesAll advisoriesCisco ASA SoftwareCisco FMC SoftwareCisco FTD SoftwareAny Platform3000 Series Industrial Security Appliances (ISA)ASA 5500-X Series FirewallsASA Service ModuleAdaptive Security Virtual Appliance (ASAv)Firepower 1000 SeriesFirepower 2100 SeriesFirepower 4100 SeriesFirepower 9000 SeriesSecure Firewall 3100 Series

  
  

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

  
  

  Additional Resources

  For help determining the best Cisco ASA, FTD, or FMC 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

  Other Platforms

  At the time of publication, the release information in the following table(s) was accurate.

  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.

  Cyber Vision: CSCwd09631

  Cisco Cyber Vision Release	First Fixed Release
  3.2.4 and earlier	Migrate to a fixed release.
  4.0	Migrate to a fixed release.
  4.1	4.1.3

  UTD Software: CSCwe57521

  Cisco UTD Software Release	First Fixed Release
  17.3	17.3.8
  17.6	17.6.6
  17.9	17.9.4
  17.11	17.11.1a
  17.12	17.12.1a

  Meraki MX Security Appliances

  Cisco Meraki MX Security Appliances Release	First Fixed Release
  MX15 and earlier	Migrate to a fixed release.
  MX16	Hot fix available for MX 16.6.6 and later.
  MX17	Hot fix available for MX 17.0 and later.
  MX18	Hot fix available for MX 18.1 and later.

  Note: No fixes will be provided for the MX64 and MX65 platforms.

  Open Source Snort Software

  Snort Release	First Fixed Release
  Snort 2	Migrate to Snort 3.
  Snort 3	3.1.32.0

  Umbrella SIG

  Cisco has addressed this vulnerability in Cisco Umbrella SIG, which is cloud based. No user action is required.

  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-snort-ftd-zXYtnjOM

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2023-NOV-01

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