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             AUSCERT External Security Bulletin Redistribution

                               ESB-2021.1467
         Multiple Cisco Products Snort HTTP Detection Engine File
                        Policy Bypass Vulnerability
                               29 April 2021

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           Series Integrated Services Routers (ISRs)
                   Series Industrial Security Appliances (ISAs)
                   Catalyst 8xxx Products
                   Cloud Services Router 1000V Series
                   Firepower Threat Defense (FTD) Software
                   Integrated Services Virtual Router (ISRv)
                   Open Source Snort 2
Publisher:         Cisco Systems
Operating System:  Cisco
Impact/Access:     Execute Arbitrary Code/Commands -- Remote/Unauthenticated
                   Unauthorised Access             -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-1495  

Original Bulletin: 
   https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-http-fp-bp-KfDdcQhc

- --------------------------BEGIN INCLUDED TEXT--------------------

Multiple Cisco Products Snort HTTP Detection Engine File Policy Bypass
Vulnerability

Priority:        Medium
Advisory ID:     cisco-sa-http-fp-bp-KfDdcQhc
First Published: 2021 April 28 16:00 GMT
Version 1.0:     Final
Workarounds:     No workarounds available
Cisco Bug IDs:   CSCvw19272 CSCvw59055
CVE Names:       CVE-2021-1495

Summary

  o 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 specific HTTP header
    parameters. 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-http-fp-bp-KfDdcQhc

Affected Products

  o Vulnerable Products

    At the time of publication, this vulnerability 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, this vulnerability 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 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 Security Appliances
       Open Source Snort 3

Workarounds

  o There are no workarounds that address this vulnerability.

Fixed Software

  o 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
    Earlier than 6.2.2 ^1        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 (May 2021)
    6.5.0                        Migrate to a fixed release.
    6.6.0                        6.6.4 ^2
    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              First Fixed Release for this
    SD-WAN Software ^1                                                                          Vulnerability
    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

    ^ 1 Starting 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 this vulnerability. For more information on open source Snort, see the
    Snort website .

Exploitation and Public Announcements

  o 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

  o This vulnerability was found by Santosh Krishnamurthy of Cisco during
    internal security testing.

Cisco Security Vulnerability Policy

  o 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.

URL

  o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-http-fp-bp-KfDdcQhc

Revision History

  o +----------+---------------------------+----------+--------+--------------+
    | Version  |        Description        | Section  | Status |     Date     |
    +----------+---------------------------+----------+--------+--------------+
    | 1.0      | Initial public release.   | -        | Final  | 2021-APR-28  |
    +----------+---------------------------+----------+--------+--------------+

- --------------------------END INCLUDED TEXT--------------------

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