Cisco Web Security Appliance Decryption Policy Bypass Vulnerability

A vulnerability in the Decryption Policy Default Action functionality of the Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to bypass a configured drop policy and allow traffic onto the network that should have been denied.

The vulnerability is due to the incorrect handling of SSL-encrypted traffic when Decrypt for End-User Notification is disabled in the configuration. An attacker could exploit this vulnerability by sending a SSL connection through the affected device. A successful exploit could allow the attacker to bypass a configured drop policy to block specific SSL connections.

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-20190206-wsa-bypass [“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190206-wsa-bypass”]