Cisco Email Security Appliance MIME Header Bypass Vulnerability

A vulnerability in the email message and content filtering for malformed Multipurpose Internet Mail Extensions (MIME) headers of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) and Web Security Appliances (WSA) could allow an unauthenticated, remote attacker to bypass the filtering functionality of the targeted device. Emails that should have been quarantined could instead be processed. The vulnerability is due to improper error handling when malformed MIME headers are present in the email attachment. An attacker could exploit this vulnerability by sending an email with a crafted attachment encoded with MIME. A successful exploit could allow the attacker to bypass the configured email message and content filtering. Cisco has released software updates that address this vulnerability. Workarounds that address this vulnerability are not available.

Checks if a vulnerable version is present on the target host.

See the referenced vendor advisory for a solution.