Valve Steam Client Application v1559/1559 Local Privilege Escalation

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Valve Steam Client Application v1559/1559 Local Privilege Escalation  
  
  
Vendor: Valve Corporation  
  
Product web page: http://www.steampowered.com  
  
Affected version: Built: Jun 1, 2011 at 15:31:24  
Steam API: v010  
Steam package versions 1559 / 1559  
File version: 1.0.968.628  
  
Summary: Steam is a digital distribution, digital rights management,  
multiplayer and communications platform developed by Valve Corporation.  
It is used to distribute games and related media online, from small  
independent developers to larger software houses. Steam also has  
community features, automated game updates, and in-game voice and  
chat functionality.  
  
Desc: Steam is vulnerable to an elevation of privileges vulnerability  
which can be used by a simple user that can change the executable file  
with a binary of choice. The vulnerability exist due to the improper  
permissions, with the "F" flag (Full Control) for the "Users" group,  
for the binary file Steam.exe, GameOverlayUI.exe and steamerrorreporter.exe.  
The binary (Steam.exe) is set by default to Startup with "-silent" parameter.  
  
Tested on: Microsoft Windows XP Professional SP3 (EN)  
  
  
Vendor status:  
  
24.06.2011 - Vulnerability discovered.  
25.06.2011 - Initial contact with the vendor.  
25.06.2011 - Auto-reply from the vendor stating that the message is received.  
28.06.2011 - No reply from the vendor.  
29.06.2011 - Public security advisory released.  
  
  
Vulnerability discovered by Gjoko 'LiquidWorm' Krstic  
liquidworm gmail com  
  
  
Advisory ID: ZSL-2011-5022  
Advisory URL: http://www.zeroscience.mk/en/vulnerabilities/ZSL-2011-5022.php  
  
  
24.06.2011  
  
  
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C:\Program Files\Steam>cacls Steam.exe  
C:\Program Files\Steam\Steam.exe BUILTIN\Users:F <---  
NT AUTHORITY\SYSTEM:F  
BUILTIN\Power Users:C  
BUILTIN\Administrators:F  
LABPC\User101:F  
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