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 detection of modified HTTP packets used in chunked responses. An attacker could exploit this vulnerability 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 this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link:https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-bypass-3eCfd24j
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 detection of modified HTTP packets used in chunked responses. An attacker could exploit this vulnerability 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 this vulnerability. There are no workarounds that address this vulnerability.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-bypass-3eCfd24j
At the time of publication, this vulnerability affected the following Cisco products if they were running a vulnerable release of Cisco software:
This vulnerability also affects the open-source Snort project version prior to 2.9.13.1. For more information, see the Snort website.
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.
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:
There are no workarounds that address this vulnerability. Please contact TAC for mitigations.
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
| Cisco FTD Software Release | First Fixed Release for This Vulnerability |
|---|---|
| 6.01 | 6.3.0.1 |
| 6.0.11 | 6.3.0.1 |
| 6.1.0 | 6.3.0.1 |
| 6.2.0 | 6.3.0.1 |
| 6.2.1 | 6.3.0.1 |
| 6.2.2 | 6.3.0.1 |
| 6.2.3 | 6.3.0.1 |
| 6.3.0 | 6.3.0.1 |
| 6.4.0 | Not vulnerable. |
| 6.5.0 | Not vulnerable. |
| 6.6.0 | Not vulnerable. |
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.
To upgrade to a fixed release of Cisco FTD Software, do one of the following:
Cisco UTD Snort IPS Engine Software for IOS XE
| UTD SNORT IPS Engine IOS XE Release | First Fixed Release for This Vulnerability |
|---|---|
| 16.9 | 16.9.5 |
| 16.12 | 16.12.2 |
| 17.1 | Not vulnerable. |
| 17.2 | Not vulnerable. |
See the Details section in the bug IDs CSCvq96573 for the most complete and current information.
Cisco UTD Engine Software for IOS XE SD-WAN
| UTD Engine IOS XE SD-WAN Release | First Fixed Release for This Vulnerability |
|---|---|
| 16.10 | 16.10.3b |
| 16.12 | 16.12.1d |
| 17.2 | Not vulnerable. |
See the Details section in the bug IDs CSCvq96573 for the most complete and current information.
Meraki MX Series Security Appliances
| Meraki MX Series Security Appliance Release | First Fixed Release for This Vulnerability |
|---|---|
| MX 14 | MX 14.53 |
| MX 15 | MX 15.33 (beta) |
Open Source SNORT
This is fixed in the open-source Snort project version 2.9.13.1 and later. For more information, see the Snort website.
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.
This vulnerability was found by Santosh Krishnamurthy of Cisco during internal security testing.
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.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.0 | Initial public release. | - | Final | 2020-OCT-21 |
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