Summary

• Multiple Cisco products are affected by vulnerabilities in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured file policy for HTTP.

  These vulnerabilities are due to incorrect handling of specific HTTP header parameters. An attacker could exploit these vulnerabilities by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass a configured file policy for HTTP packets and deliver a malicious payload.

  Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities. 

  This advisory is available at the following link:
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-http-fp-bp-KfDdcQhc

Affected Products

• Vulnerable Products

  At the time of publication, these vulnerabilities affected all open source Snort project releases earlier than Release 2.9.17.1. For more information on open source Snort, see the Snort website.

  At the time of publication, these vulnerabilities affected the following Cisco products if they were running a vulnerable release of Cisco UTD Snort IPS Engine Software for Cisco IOS XE Software or Cisco UTD Engine for Cisco IOS XE SD-WAN Software and were configured with a Snort HTTP Detection Engine File Policy:

  • 1000 Series Integrated Services Routers (ISRs)
  • 3000 Series Industrial Security Appliances (ISAs)
  • 4000 Series Integrated Services Routers (ISRs)
  • Catalyst 8000V Edge Software
  • Catalyst 8200 Series Edge Platforms
  • Catalyst 8300 Series Edge Platforms
  • Catalyst 8500L Series Edge Platforms
  • Cloud Services Router 1000V Series
  • Firepower Threat Defense (FTD) Software
  • Integrated Services Virtual Router (ISRv)
  • Open Source Snort 2

  For information about which Cisco software releases were vulnerable at the time of release, 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 these vulnerabilities.

  Cisco has confirmed that these vulnerabilities do not affect the following Cisco products:

  • Adaptive Security Appliance (ASA) Software
  • Catalyst 8500 Series Edge Platforms
  • Firepower Management Center (FMC) Software
  • Meraki Security Appliances
  • Open Source Snort 3

Workarounds

• There are no workarounds that address these vulnerabilities.

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 vulnerabilities described in this advisory and which release included the fix for these vulnerabilities.

  Cisco FTD Software

  Cisco FTD Software Release	First Fixed Release for these Vulnerabilities
  Earlier than 6.2.21	Migrate to a fixed release.
  6.2.2	Migrate to a fixed release.
  6.2.3	Migrate to a fixed release.
  6.3.0	Migrate to a fixed release.
  6.4.0	6.4.0.12
  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.

  Cisco IOS XE Software and Cisco IOS XE SD-WAN Software

  Cisco UTD Snort IPS Engine Software for IOS XE and Cisco UTD Engine for IOS XE SD-WAN Software1	First Fixed Release for these Vulnerabilities
  Earlier than 16.12	Migrate to a fixed release.
  16.12	16.12.5
  17.1	Migrate to a fixed release.
  17.2	Migrate to a fixed release.
  17.3	17.3.3
  17.4	17.4.1

  ¹Starting with release 17.2.1, Cisco IOS XE Software and Cisco IOS XE SD-WAN Software share the same image file.

  Open Source Snort

  The open source Snort project releases 2.9.17.1 and later contain the fix for these vulnerabilities. For more information on open source Snort, see the Snort website.

Exploitation and Public Announcements

• The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.

Source

• These vulnerabilities were found by Santosh Krishnamurthy of Cisco during internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-http-fp-bp-KfDdcQhc

Revision History

• Version	Description	Section	Status	Date
  1.1	Added CVE-2021-1494 to the advisory	—	Final	2021-MAY-20
  1.0	Initial public release.	—	Final	2021-APR-28

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