News
Vigil@nce - Cisco Email Security Appliance: filtering bypass via SPF
August 2015 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
An attacker can send a specially crafted DNS SPF response to Cisco
Email Security Appliance, in order to bypass the filtering rules
for SMTP.
Impacted products: AsyncOS, Cisco ESA.
Severity: 2/4.
Creation date: 15/06/2015.
DESCRIPTION OF THE VULNERABILITY
The Cisco Email Security Appliance product includes an anti-spam
filter.
It uses the "Sender Policy Framework", a way to state via DNS
records, which hosts may send e-mail for the queried domain about.
However, for some specially crafted packet, Cisco ESA always
grants send authorization.
An attacker can therefore send a specially crafted DNS SPF
response to Cisco Email Security Appliance, in order to bypass the
filtering rules for SMTP.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/Cisco-Email-Security-Appliance-filtering-bypass-via-SPF-17131
