Cisco AsyncOS Software ZIP Filtering Bypass Vulnerability

A vulnerability in the ZIP inspection engine of Cisco AsyncOS for Cisco Email Security
Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the engine protection and deliver malicious ZIP files.

The
vulnerability is due to improper implementation of the logic for analyzing
the content of a ZIP file. An attacker could exploit this vulnerability by crafting the ZIP file before sending it through the system.

Cisco has confirmed the vulnerability in a security notice and released software updates.

An exploit of this vulnerability could allow an attacker to bypass security restrictions on a targeted system, which could be used to send malicious ZIP files to be processed by the system. Processing the malicious ZIP files could be used to conduct further attacks.

Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.