Summary

• Multiple Cisco products are affected by a vulnerability in the way the Snort detection engine processes ICMP traffic that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

  The vulnerability is due to improper memory resource management while the Snort detection engine is processing ICMP packets. An attacker could exploit this vulnerability by sending a series of ICMP packets through an affected device. A successful exploit could allow the attacker to exhaust resources on the affected device, causing the device to reload.

  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-dos-s2R7W9UU

  This advisory is part of the October 2021 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: October 2021 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication.

Affected Products

• Vulnerable Products

  At the time of publication, this vulnerability affected all open source Snort project releases earlier than Release 2.9.18. For more information on open source Snort, see the Snort website.

  Impact to Cisco Products

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

  • Firepower Threat Defense (FTD) Software - All platforms

  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.

  Note: UTD is not installed on these devices by default:

  • 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
  • Cloud Services Routers 1000V Series
  • Integrated Services Virtual Routers (ISRv)

  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:

  • Adaptive Security Appliance (ASA) Software
  • Catalyst 8500 Series Edge Platforms
  • Catalyst 8500L Series Edge Platforms
  • Firepower Management Center (FMC) Software
  • Meraki Security 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

  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.

  Cisco FTD Software

  FTD Software Release	First Fixed Release for This Vulnerability
  6.2.2 and earlier1	Migrate to a fixed release.
  6.2.3	Migrate to a fixed release.
  6.3.01	Migrate to a fixed release.
  6.4.0	6.4.0.12
  6.5.01	Migrate to a fixed release.
  6.6.0	6.6.3
  6.7.0	6.7.0.2
  7.0.0	Not vulnerable.

  1. Cisco FMC and FTD Software releases 6.2.2 and earlier, as well as releases 6.3.0 and 6.5.0, have reached end of software maintenance. Customers are advised to migrate to a supported release that includes the fix for this vulnerability.

  
  

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

  Cisco UTD Software

  UTD Software Release	First Fixed Release for This Vulnerability
  16.12	16.12.6
  17.3	17.3.4a
  17.4	17.4.2
  17.5	Not vulnerable.
  17.6	Not vulnerable.
  17.7	Not vulnerable.

  Snort Software Release

  Snort Major Release	First Fixed Release for This Vulnerability
  2.x	2.9.18
  3.x	Not vulnerable.

  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 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 Santosh Krishnamurthy of Cisco during internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-dos-s2R7W9UU

Revision History

• Version	Description	Section	Status	Date
  1.1	Updated the Source section.	Source	Final	2021-OCT-29
  1.0	Initial public release.	-	Final	2021-OCT-27

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