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             AUSCERT External Security Bulletin Redistribution

    Cisco Adaptive Security Appliance Software Release 9.16.1 and Cisco
       Firepower Threat Defense Software Release 7.0.0 IPsec Denial
                         of Service Vulnerability
                               19 July 2021


        AusCERT Security Bulletin Summary

Product:           Adaptive Security Appliance (ASA)
                   Firepower Threat Defense (FTD)
Publisher:         Cisco Systems
Operating System:  Cisco
Impact/Access:     Denial of Service -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-1422  

Original Bulletin: 

Revision History:  July 19 2021: Vendor updated the first fixed release for the ASA platform
                   July 16 2021: Initial Release

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Cisco Adaptive Security Appliance Software Release 9.16.1 and Cisco Firepower
Threat Defense Software Release 7.0.0 IPsec Denial of Service Vulnerability

Priority:        High
Advisory ID:     cisco-sa-asa-ftd-ipsec-dos-TFKQbgWC
First Published: 2021 July 15 16:00 GMT
Last Updated:    2021 July 16 14:57 GMT
Version 1.1:     Final
Workarounds:     No workarounds available
Cisco Bug IDs:   CSCvy66711
CVE Names:       CVE-2021-1422
CWEs:            CWE-617


  o A vulnerability in the software cryptography module of Cisco Adaptive
    Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD)
    Software could allow an authenticated, remote attacker or an
    unauthenticated attacker in a man-in-the-middle position to cause an
    unexpected reload of the device that results in a denial of service (DoS)

    The vulnerability is due to a logic error in how the software cryptography
    module handles specific types of decryption errors. An attacker could
    exploit this vulnerability by sending malicious packets over an established
    IPsec connection. A successful exploit could cause the device to crash,
    forcing it to reload. Important : Successful exploitation of this
    vulnerability would not cause a compromise of any encrypted data.

    Note: This vulnerability affects only Cisco ASA Software Release 9.16.1 and
    Cisco FTD Software Release 7.0.0.

    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:

Affected Products

  o Vulnerable Products

    This vulnerability affects the following Cisco products if they are running
    Cisco ASA Software Release 9.16.1 or Cisco FTD Software Release 7.0.0 and
    are configured to support IPsec connections to the device.

       Firepower 2100 Series
       Firepower NGFW Virtual
       Adaptive Security Virtual Appliance (ASAv)

    Note: These devices are not vulnerable if Federal Information Processing
    Standards Publication (FIPS) mode is enabled.

    For information about which Cisco software releases are vulnerable, see the
    Fixed Software section of this advisory.

    Determine the Device Configuration

    The device should be considered vulnerable if either of these configuration
    parameters exists on the device:

     1. If there is a crypto map bound to an interface in the configuration.
        The administrator can issue the show running-config command and check
        for the crypto map interface command.

     2. If there is a crypto IPsec profile bound to a tunnel interface in the
        configuration. The administrator can issue the show running-config 
        command and check for the tunnel protection ipsec command.

    The device is considered not vulnerable if FIPS mode is enabled.

     1. For ASA Software, the administrator can issue the show running-config |
        include fips-enable command and if the output contains the fips-enable 
        keyword the device is considered not vulnerable.

     2. In Cisco FTD Software, FIPS mode is enabled indirectly by configuring
        either Common Criteria (CC) mode or Unified Capabilities Approved
        Products List (UCAPL) mode. For further information on determining if
        FIPS is configured for Cisco FTD Software, see the Security
        Certifications Compliance chapter of the Firepower Management Center
        Configuration Guide .

    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 Cisco ASA
    Software and Cisco FTD Software running on any platform other than the
    platforms listed in the Vulnerable Products section.

    In addition, Cisco has confirmed that this vulnerability does not affect
    Cisco Firepower Management Center (FMC) Software.


  o There are no workarounds that address this vulnerability.

Fixed Software

  o Cisco has released free software updates that address the vulnerability
    described in this advisory. Customers may only install and expect support
    for software versions and feature sets for which they have purchased a
    license. By installing, downloading, accessing, or otherwise using such
    software upgrades, customers agree to follow the terms of the Cisco
    software license:

    Additionally, customers may only download software for which they have a
    valid license, procured from Cisco directly, or through a Cisco authorized
    reseller or partner. In most cases this will be a maintenance upgrade to
    software that was previously purchased. Free security software updates do
    not entitle customers to a new software license, additional software
    feature sets, or major revision upgrades.

    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

    Customers Without Service Contracts

    Customers who purchase directly from Cisco but do not hold a Cisco service
    contract and customers who make purchases through third-party vendors but
    are unsuccessful in obtaining fixed software through their point of sale
    should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c

    Customers should have the product serial number available and be prepared
    to provide the URL of this advisory as evidence of entitlement to a free

    Fixed Releases

    This vulnerability is fixed in Cisco ASA Software releases and

    This vulnerability is fixed for Cisco Firepower 2100 Series by

    This vulnerability is fixed for Cisco Firepower NGFW Virtual by

    Note: This vulnerability affects only Cisco ASA Software Release 9.16.1 and
    Cisco FTD Software Release 7.0.0.

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.


  o This vulnerability was found during the resolution of a Cisco TAC support

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.


  o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-ipsec-dos-TFKQbgWC

Revision History

  o +---------+-----------------------------+----------+--------+-------------+
    | Version |         Description         | Section  | Status |    Date     |
    |         | Updated the first fixed     | Fixed    |        |             |
    | 1.1     | release for the ASA         | Software | Final  | 2021-JUL-16 |
    |         | platform.                   |          |        |             |
    | 1.0     | Initial public release.     | -        | Final  | 2021-JUL-15 |

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