Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services VPN Denial of Service Vulnerabilities

Multiple vulnerabilities in Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.

These vulnerabilities are due to lack of proper input validation of the HTTPS request. An attacker could exploit these vulnerabilities by sending a crafted HTTPS request to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

Note: This vulnerability affects only specific AnyConnect and WebVPN configurations. For more information, see the Vulnerable Products [“#vp”] section.

Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.

This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-vpn-dos-fpBcpEcD [“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-vpn-dos-fpBcpEcD”]

This advisory is part of the April 2021 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: April 2021 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication [“https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74594”].