Valve Steam Client Application v1559/1559 Local Privilege Escalation

ID 1337DAY-ID-16428
Type zdt
Reporter LiquidWorm
Modified 2011-06-29T00:00:00


Exploit for windows platform in category local exploits

                                            Valve Steam Client Application v1559/1559 Local Privilege Escalation
Vendor: Valve Corporation
Product web page:
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:
C:\Program Files\Steam>cacls Steam.exe
C:\Program Files\Steam\Steam.exe BUILTIN\Users:F <---
                                 NT AUTHORITY\SYSTEM:F
                                 BUILTIN\Power Users:C

# [2018-01-02]  #