CVE-2022-20713: Cisco Security Advisory: Cisco Adaptive Security Appliance Software Clientless SSL VPN Client-Side Request Smuggling Vulnerability

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Summary

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• A vulnerability in the Clientless SSL VPN (WebVPN) component of Cisco Adaptive Security Appliance (ASA) Software could allow an unauthenticated, remote attacker to conduct browser-based attacks.

  This vulnerability is due to improper validation of input that is passed to the Clientless SSL VPN component. An attacker could exploit this vulnerability by convincing a targeted user to visit a website that can pass malicious requests to an ASA device that has the Clientless SSL VPN feature enabled. A successful exploit could allow the attacker to conduct browser-based attacks, including cross-site scripting attacks, against the targeted user.

  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-asa-webvpn-LOeKsNmO

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Affected Products

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• At the time of publication, this vulnerability affected Cisco devices if they were running a release of Cisco ASA Software earlier than Release 9.17(1) and had the Clientless SSL VPN feature enabled.

  Note: Cisco deprecated support for the Clientless SSL VPN feature in Cisco ASA Software Release 9.17(1). See the Release Notes for the Cisco ASA Series, 9.17(x) for additional information.

  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 Cisco Firepower Threat Defense (FTD) Software.

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Workarounds

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• There are no workarounds that address this vulnerability. However, customers may consider disabling the Clientless SSL VPN feature.

  While this mitigation has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.

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Fixed Software

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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

  For information about fixed software releases, see the Details section in the bug ID(s) at the top of this advisory.

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Exploitation and Public Announcements

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• 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.

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Source

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

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Cisco Security Vulnerability Policy

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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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URL

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Revision History

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• Version

  Description

  Section

  Status

  Date

  1.0

  Initial public release.

  -

  Final

  2022-AUG-10

  Show Less

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Legal Disclaimer

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  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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