Cisco Security Advisory: Cisco Email Security Appliance Anti-Spam Scanner Bypass Vulnerability

Cisco Email Security Appliance Anti-Spam Scanner Bypass Vulnerability

Advisory ID: cisco-sa-20150612-esa

Revision 2.0

For Public Release 2015 November 4 16:00 UTC (GMT)

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Summary
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A vulnerability in the anti-spam scanner of Cisco AsyncOS for Cisco
Email Security Appliance (ESA) could allow an unauthenticated, remote
attacker to bypass the anti-spam functionality of the ESA.

The vulnerability is due to improper error handling of a malformed
packet in the anti-spam scanner. An attacker could exploit this
vulnerability by sending a crafted DNS Sender Policy Framework (SPF)
text record. A successful exploit could allow the attacker to bypass
the anti-spam scanner and generate a malformed packet alert.

Cisco has released software updates that address this vulnerability.
There are no workarounds that mitigate this vulnerability.

This advisory is available at the following link:

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20150612-esa