Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software WebVPN Portal Access Rule Bypass Vulnerability

Update from October 22nd, 2020: Cisco has become aware of a new Cisco Adaptive Security Appliance vulnerability that could affect the fixed releases recommended for code trains 9.13 and 9.14 in the Fixed Software [“#fs”] section of this advisory. See the Cisco Adaptive Security Appliance Software SSL/TLS Denial of Service Vulnerability [“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ssl-dos-7uZWwSEy”] for additional information.

A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass a configured access rule and access parts of the WebVPN portal that are supposed to be blocked.

The vulnerability is due to insufficient validation of URLs when portal access rules are configured. An attacker could exploit this vulnerability by accessing certain URLs on 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-asaftd-rule-bypass-P73ABNWQ [“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-rule-bypass-P73ABNWQ”]