Cisco Email Security Appliance Corrupted Attachment Fields Denial of Service Vulnerability

A vulnerability in the email message filtering feature of Cisco AsyncOS Software for Cisco Email Security Appliances could allow an unauthenticated, remote attacker to cause an affected device to stop scanning and forwarding email messages due to a denial of service (DoS) condition.

The vulnerability is due to improper input validation of email attachments that have corrupted fields. An attacker could exploit this vulnerability by sending a crafted email message, which has an attachment with corrupted fields, through an affected device. When the affected software filters the attachment, the filtering process could crash and restart, resulting in a DoS condition. After the filtering process restarts, the software resumes filtering for the same attachment, causing the filtering process to crash and restart again. A successful exploit could allow the attacker to cause a repeated DoS condition.

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-20161026-esa3[“https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20161026-esa3”]