Cisco Security Advisory
Multiple Cisco Products Snort HTTP Detection Engine File Policy Bypass Vulnerability
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CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N/E:X/RL:X/RC:X
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Multiple Cisco products are affected by a vulnerability in the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured file policy for HTTP.
The vulnerability is due to incorrect handling of an HTTP range header. An attacker could exploit this vulnerability by sending crafted HTTP packets through an affected device. A successful exploit could allow the attacker to bypass configured file policy for HTTP packets 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-filepolbypass-67DEwMe2
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Vulnerable Products
At the time of publication, this vulnerability affected all open source Snort project releases earlier than Release 2.9.17. For more information, see the Snort website.
At the time of publication, this vulnerability affected the following Cisco products if they were running a vulnerable release of Cisco software:
- 3000 Series Industrial Security Appliances (ISAs)
- Firepower Threat Defense (FTD) Software
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 Protection 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)
- Cloud Services Router 1000V
- Integrated Services Virtual Router (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
- Firepower Management Center (FMC) Software
- Meraki Security Appliances
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There are no workarounds that address this vulnerability.
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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, Cisco Firepower Threat Defense (FTD) releases 6.7.0 and later contained the fix for this vulnerability.
At the time of publication, Cisco UTD Snort IPS Engine Software for IOS XE 17.4.11 contained the fix for this vulnerability.
At the time of publication, open source Snort project releases 2.9.17 and later contained the fix for this vulnerability. For more information, see the Snort website.
See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.
1. Starting in 17.2.1, IOS XE and IOS XE SD-WAN use the same image file.
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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.
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This vulnerability was found by Ilkin Gasimov of Cisco during internal security testing.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Show LessVersion Description Section Status Date 1.1 Added Unified Threat Defense release information. Vulnerable Products Final 2021-APR-30 1.0 Initial public release. - Final 2021-JAN-13
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