weak activationid and password generator

[chinchilla2k]

Hi, I was originally going to get an admin account on this site using this method but tbh I've already donated hours trying to find the best way to pull it off. I wanna get working on something else now.

When you use the "forgot password" dealie it emails you a link that will reset the password to something "randomly" generated. The link is something like

http://antionline.com/login.php?a=pw...431&i=73954595

The 'i' at the end is a validation ID used as a security measure to prevent users from resetting other user's passwords. However the way they generate it is gay.

line 183 in login.php

$user['activationid'] = build_user_activation_id($user['userid'], 2, 1); 

line 580 in functions_user.php (within the function build_user_activation_id)

$activateid = vbrand(0,100000000); 

and finally lines 318-332 in functions.php

function vbrand($min, $max, $seed = -1)
{
    if (!defined('RAND_SEEDED'))
    {
        if ($seed == -1)
        {
            $seed = (double) microtime() * 1000000;
        }
        mt_srand($seed);
        define('RAND_SEEDED', true);
    }
    return mt_rand($min, $max);
} 

All you really have to know is that random number generators aren't random at all, that's why they're called pseudo random number generators. Given the same seed a prng will generate the same "random" numbers. In vbrand() we see that if the prng isn't seeded it will seed it with

(double) microtime() * 1000000; 

For which there are only 1 million possibilties of. Another point to mention is that a single seed from 0-1mil will also have a duplicate. So really there are only 500k possibilties for the validation ID (if the seed is even, then seed + 1 will generate the same random numbers).

The randomly generated password is created using the same method, so the same principles apply.

My main problem was that vBulletin only allows 5 bad logins every 15 minutes from a single IP. This is a problem because I would have to try to login with all 500k possible passes. I was planning to defeat this by either abusing tor or hunting for thousands of proxies, both which would've taken up alot of time. (and wouldn'tve been reliable)

I had also considered taking advantage of using a login cookie, bbpassword value in the cookie was generated using

md5(md5(md5($password) . $vbulletin->userinfo['salt']), '') . COOKIE_SALT) 

I could've predicted cookie_salt but the user salt, despite being only 3 symbols long, makes it impractical to use.

So at the moment the most I'd be able to easily do is just reset people's passes, which sucks.

PS
when you receive a lost password request is processed the IP of the user who requested the password change isn't stored anywhere, so had I managed to reset a user's password, all they would be able to do is speculate from server logs who reset it.

PPS
I wouldn't have to try to login with all 500k possible passes if I could coordinate it so that the server processes my request at a certain microtime. I could've potentially eliminated it down to 50k possible passes.. maybe even less.

PPPS
This applies to the latest vBulletin board. I managed to predict the passwords + validation ids on other major vBulletin boards too. so yea..


The following code generates all possible validation ids and passwords generated by vBulletin.

<?php
for($i = 0; $i < 1000000; $i+=2) {
    mt_srand($i);
    print mt_rand(0, 100000000) . "\r\n";
}
?>

or if you want a hardcopy
http://www.freewebtown.com/cyberhacker665/output.txt


a t t r i t i o n . o r g > AO (I read about this site from them, lol, shame on you JP for shutting down packetstorm )

I can be reached at irc.iris-network.net #80h