This script is Copyright (C) 2005-2013 Tenable Network Security, Inc.
The remote mail server is vulnerable to a denial of service attack.
The remote host is running Courier Mail Server, an open source mail
server for Linux and Unix.
According to its banner, the installed version of Courier is prone to
a remote denial of service vulnerability triggered when doing Sender
Policy Framework (SPF) data lookups. To exploit this flaw, an
attacker would need to control a DNS server and return malicious SPF
records in response to queries from the affected application.
Upgrade to Courier version 0.50.1 or later.
Risk factor :
Low / CVSS Base Score : 2.6
CVSS Temporal Score : 1.9
Public Exploit Available : false