Valve Steam Client Application v1559/1559 Local Privilege Escalation

2011-06-29T00:00:00
ID ZSL-2011-5022
Type zeroscience
Reporter Gjoko Krstic
Modified 2011-06-29T00:00:00

Description

Title: Valve Steam Client Application v1559/1559 Local Privilege Escalation
Advisory ID: ZSL-2011-5022
Type: Local
Impact: Privilege Escalation
Risk: (3/5)
Release Date: 29.06.2011

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.

Description

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.

Vendor

Valve Corporation - <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

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.

PoC

steam_privesc.txt

Credits

Vulnerability discovered by Gjoko Krstic - <gjoko@zeroscience.mk>

References

[1] <http://www.exploit-db.com/exploits/17459/>
[2] <http://packetstormsecurity.org/files/102666>
[3] <http://securityreason.com/exploitalert/10548>
[4] <http://www.securityfocus.com/bid/48504>
[5] <http://xforce.iss.net/xforce/xfdb/68333>
[6] <http://www.vfocus.net/art/20110630/9171.html>

Changelog

[29.06.2011] - Initial release
[30.06.2011] - Added reference [1], [2] and [3]
[01.07.2011] - Added reference [4] and [5]
[02.07.2011] - Added reference [6]

Contact

Zero Science Lab

Web: <http://www.zeroscience.mk>
e-mail: lab@zeroscience.mk

                                        
                                            
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


------------------------------------------------------------


C:\Program Files\Steam&gt;cacls Steam.exe
C:\Program Files\Steam\Steam.exe BUILTIN\Users:F &lt;---
                                 NT AUTHORITY\SYSTEM:F
                                 BUILTIN\Power Users:C
                                 BUILTIN\Administrators:F
                                 LABPC\User101:F