Operating System:

[Cisco]

Published:

22 December 2022

Protect yourself against future threats.

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             AUSCERT External Security Bulletin Redistribution

                              ESB-2022.3979.4
         Cisco Adaptive Security Appliance Software Clientless SSL
              VPN Client-Side Request Smuggling Vulnerability
                             22 December 2022

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

Product:           Cisco Adaptive Security Appliance Software
Publisher:         Cisco Systems
Operating System:  Cisco
Resolution:        Mitigation
CVE Names:         CVE-2022-20713  

Original Bulletin: 
   https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-webvpn-LOeKsNmO

Comment: CVSS (Max):  4.3 CVE-2022-20713 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N)
         CVSS Source: Cisco Systems
         Calculator:  https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Revision History:  December 22 2022: Updated information about fixed software availability
                   November 11 2022: Updated Subject to include CVSS Score
                   November 10 2022: Vendor updated bulletin
                   August   11 2022: Initial Release

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Cisco Adaptive Security Appliance and Firepower Threat Defense Software VPN Web
Client Services Client-Side Request Smuggling Vulnerability

Priority:        Medium
Advisory ID:     cisco-sa-asa-webvpn-LOeKsNmO
First Published: 2022 August 10 16:00 GMT
Last Updated:    2022 December 16 18:00 GMT
Version 2.1:     Final
Workarounds:     No workarounds available
Cisco Bug IDs:   CSCwa04262
CVE Names:       CVE-2022-20713

Summary

  o A vulnerability in the VPN web client services component of Cisco Adaptive
    Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD)
    Software could allow an unauthenticated, remote attacker to conduct
    browser-based attacks against users of an affected device.

    This vulnerability is due to improper validation of input that is passed to
    the VPN web client services component before being returned to the browser
    that is in use. An attacker could exploit this vulnerability by persuading
    a user to visit a website that is designed to pass malicious requests to a
    device that is running Cisco ASA Software or Cisco FTD Software and has web
    services endpoints supporting VPN features enabled. A successful exploit
    could allow the attacker to reflect malicious input from the affected
    device to the browser that is in use and conduct browser-based attacks,
    including cross-site scripting attacks. The attacker could not directly
    impact the affected device.

    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-asa-webvpn-LOeKsNmO

Affected Products

  o Vulnerable Products

    At the time of publication, this vulnerability affected Cisco products if
    they were running a vulnerable release of the following Cisco software:

       ASA Software with Cisco AnyConnect VPN or Clientless SSL VPN enabled
       FTD Software with Cisco AnyConnect VPN enabled

    See the Details section in the bug ID(s) at the top of this advisory for
    the most complete and current information.

    Determine the ASA Software Configuration

    To determine whether the software has a vulnerable feature enabled, use the
    show-running-config CLI command. In the following table, the left column
    lists the Cisco ASA Software features that are vulnerable. The right column
    indicates the basic configuration for each feature from the show
    running-config CLI command. If a device is running a vulnerable release and
    has one of these features enabled, it is vulnerable.

    Cisco ASA Feature                Vulnerable Configuration
    AnyConnect Internet Key Exchange crypto ikev2 enable  client-services port
    Version 2 Remote Access (with
    client services)
                                     webvpn
    AnyConnect SSL VPN                enable

    Clientless SSL VPN               webvpn
                                      enable

    Determine the FTD Software Configuration

    To determine whether the software has a vulnerable feature enabled, use the
    show-running-config CLI command. In the following table, the left column
    lists the Cisco FTD Software features that are vulnerable. The right column
    indicates the basic configuration for each feature from the show
    running-config CLI command. If a device is running a vulnerable release and
    has one of these features enabled, it is vulnerable.

    Cisco FTD Feature                Vulnerable Configuration
    AnyConnect Internet Key Exchange crypto ikev2 enable  client-services port
    Version 2 Remote Access (with
    client services) ^1,2
    AnyConnect SSL VPN ^1,2          webvpn
                                      enable

    1. Remote Access VPN features were introduced in Cisco FTD Software Release
    6.2.2.
    2. Remote Access VPN features are enabled by using Devices > VPN > Remote
    Access in Cisco Firepower Management Center (FMC) or by using Device >
    Remote Access VPN in Cisco Firepower Device Manager (FDM).

    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 devices with remote access VPN services that are
    configured to accept only AnyConnect Internet Key Exchange Version 2 Remote
    Access VPN with client services disabled are not affected by this
    vulnerability.

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.

    Cisco ASA, FMC, and FTD Software

    To help customers determine their exposure to vulnerabilities in Cisco ASA,
    FMC, and FTD Software, Cisco provides the Cisco Software Checker . This
    tool identifies any Cisco security advisories that impact a specific
    software release and the earliest release that fixes the vulnerabilities
    that are described in each advisory ("First Fixed"). If applicable, the
    tool also returns the earliest release that fixes all the vulnerabilities
    that are described in all the advisories that the Software Checker
    identifies ("Combined First Fixed").

    To use the tool, go to the Cisco Software Checker page and follow the
    instructions. Alternatively, use the following form to search for
    vulnerabilities that affect a specific software release. To use the form,
    follow these steps:

     1. Choose which advisories the tool will search-all advisories, only
        advisories with a Critical or High Security Impact Rating (SIR) , or
        only this advisory.
     2. Choose the appropriate software.
     3. Choose the appropriate platform.
     4. Enter a release number-for example, 9.16.2.11 for Cisco ASA Software or
        6.6.7 for Cisco FTD Software.
     5. Click Check .
    [2                   ] [                    ] [Critical,High,Medium] 
    [Only this advisory              ] [Cisco ASA Software] 
    [Any Platform                                    ]

    [                    ] [Check]

Exploitation and Public Announcements

  o The Cisco Product Security Incident Response Team (PSIRT) is aware that
    proof-of-concept exploit code is available for the vulnerability described
    in this advisory.

    The Cisco PSIRT is not aware of any malicious use of the vulnerability that
    is described in this advisory.

Source

  o Cisco would like to thank James Kettle of Portswigger.net for reporting
    this vulnerability.

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.

Subscribe to Cisco Security Notifications

  o Subscribe

Related to This Advisory

  o 

URL

  o https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-webvpn-LOeKsNmO

Revision History

  o +---------+-----------------------+----------------+--------+-------------+
    | Version |      Description      |    Section     | Status |    Date     |
    +---------+-----------------------+----------------+--------+-------------+
    |         | Updated information   | Summary, Fixed |        |             |
    | 2.1     | about fixed software  | Software       | Final  | 2022-DEC-16 |
    |         | availability.         |                |        |             |
    +---------+-----------------------+----------------+--------+-------------+
    |         | Added FTD Software as | Title,         |        |             |
    |         | an affected product.  | Summary,       |        |             |
    |         | Updated the affected  | Vulnerable     |        |             |
    |         | VPN component.        | Products,      |        |             |
    | 2.0     | Clarified affected    | Products       | Final  | 2022-NOV-09 |
    |         | software              | Confirmed Not  |        |             |
    |         | configurations.       | Vulnerable,    |        |             |
    |         | Removed the           | and            |        |             |
    |         | mitigation because it | Workarounds    |        |             |
    |         | no longer applies.    |                |        |             |
    +---------+-----------------------+----------------+--------+-------------+
    | 1.0     | Initial public        | -              | Final  | 2022-AUG-10 |
    |         | release.              |                |        |             |
    +---------+-----------------------+----------------+--------+-------------+

Legal Disclaimer

  o THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND
    OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR
    FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT
    OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES
    THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.

    A standalone copy or paraphrase of the text of this document that omits the
    distribution URL is an uncontrolled copy and may lack important information
    or contain factual errors. The information in this document is intended for
    end users of Cisco products.

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