PHP ip2long() function circumvention Jul 29 2006 07:26AM
rgod autistici org
--- PHP ip2long() function circumvention --------------------------------------

tested on php 5.0.2

" 4.3.3


after some test on miniBB application (http://www.minibb.net/) I obtained that

the php ip2long() function can be tricked to return a valid IPv4 Internet

network address instead of "-1" even if the ip address argument is not a valid

one, through the injection of some chars, ex:


for ($i=0; $i<=255; $i++)


echo $i.":".ip2long("".chr($i)."'or'a'='a'/*")."\r\n";



when chr($i) is chr(0), chr(9), chr(10), chr(11), chr(12), chr(13) or chr(32)

it gives the following (valid) result:


in minibb case this could result in sql injection, forging an header like this:


or even like this:


(however Minibb limit the string to 15 chars so you will have an unuseful twelve

chars sql injection...)

also remeber that HTTP headers is not filtered by PHP magic_quotes_gpc, so this

could give an attacker the way to fully compromise an application

code taken from MiniBB 2.0

index.php, 248-264

/* Banned IPs/IDs stuff */

$thisIp=getIP(); <--------------------- here $thisIp becomes our sql code

$cen=explode('.', $thisIp);

if(isset($cen[0]) and isset($cen[1]) and isset($cen[2])){




else {




if (db_ipCheck($thisIp,$thisIpMask,$user_id)) { //<----------- $thisIp is passed to the db_ipCheck() function

$title=$sitename." :: ".$l_accessDenied;

echo ParseTpl(makeUp('main_access_denied')); exit;


bb_functions.php, near lines 123-131


function getIP(){


if ($ip2!='' and ip2long($ip2)!=-1) $finalIP=$ip2; else $finalIP=$ip1; //<-- vulnerable code


return $finalIP;



setup_mysql.php, near lines 99-105:

function db_ipCheck($thisIp,$thisIpMask,$user_id){

$res=mysql_query('select id from '.$GLOBALS['Tb'].' where

banip='."'".$thisIp."'".' or banip='."'".$thisIpMask[0]."'".' or //<--- sql injection

banip='."'".$thisIpMask[1]."'".' or banip='."'".$user_id."'");

echo mysql_error();

if($res and mysql_num_rows($res)>0) return TRUE; else return FALSE;



1.05 29/07/2006




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