Cisco Web Security Appliance HTTPS Certificate Denial of Service Vulnerability

A vulnerability in the HTTPS decryption feature of Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.

The vulnerability is due to insufficient validation of Secure Sockets Layer (SSL) server certificates. An attacker could exploit this vulnerability by installing a malformed certificate in a web server and sending a request to it through the Cisco WSA. A successful exploit could allow the attacker to cause an unexpected restart of the proxy process on an 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-20190703-wsa-dos [“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190703-wsa-dos”]