Ubisoft Uplay 4.6 Insecure File Permissions Local Privilege Escalation


Vendor: Ubisoft Entertainment S.A.
Product web page: http://www.ubi.com
Affected version: 4.6.3208 (PC)
                  4.5.2.3010 (PC)


Summary: Uplay is a digital distribution, digital rights management,
multiplayer and communications service created by Ubisoft to provide
an experience similar to the achievements/trophies offered by various
other game companies.

 - Uplay PC is a desktop client which replaces individual game launchers
 previously used for Ubisoft games. With Uplay PC, you have all your Uplay
 enabled games and Uplay services in the same place and you get access to
 a whole new set of features for your PC games.

Desc: Uplay for PC suffers from 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) for 'Everyone' group, making the
entire directory 'Ubisoft Game Launcher' and its files and sub-dirs
world-writable.

Tested on: Microsoft Windows 7 Professional SP1 (EN)
           Microsoft Windows 7 Ultimate SP1 (EN)


Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
                            @zeroscience


Advisory ID: ZSL-2014-5191
Advisory URL: http://www.zeroscience.mk/en/vulnerabilities/ZSL-2014-5191.php

Vendor: http://forums.ubi.com/forumdisplay.php/513-Uplay


30.05.2014

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C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher>icacls *.exe |findstr Everyone
UbisoftGameLauncher.exe Everyone:(I)(F)
UbisoftGameLauncher64.exe Everyone:(I)(F)
Uninstall.exe Everyone:(I)(F)
Uplay.exe Everyone:(I)(F)
UplayCrashReporter.exe Everyone:(I)(F)
UplayService.exe Everyone:(I)(F)

C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher>


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C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher>icacls Uplay.exe
Uplay.exe Everyone:(I)(F)
          NT AUTHORITY\SYSTEM:(I)(F)
          BUILTIN\Administrators:(I)(F)
          BUILTIN\Users:(I)(RX)

Successfully processed 1 files; Failed processing 0 files

C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher>

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C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher>icacls *.exe |findstr (F)
UbisoftGameLauncher.exe Everyone:(I)(F)
                        NT AUTHORITY\SYSTEM:(I)(F)
                        BUILTIN\Administrators:(I)(F)
UbisoftGameLauncher64.exe Everyone:(I)(F)
                          NT AUTHORITY\SYSTEM:(I)(F)
                          BUILTIN\Administrators:(I)(F)
Uninstall.exe Everyone:(I)(F)
              NT AUTHORITY\SYSTEM:(I)(F)
              BUILTIN\Administrators:(I)(F)
Uplay.exe Everyone:(I)(F)
          NT AUTHORITY\SYSTEM:(I)(F)
          BUILTIN\Administrators:(I)(F)
UplayCrashReporter.exe Everyone:(I)(F)
                       NT AUTHORITY\SYSTEM:(I)(F)
                       BUILTIN\Administrators:(I)(F)
UplayService.exe Everyone:(I)(F)
                 NT AUTHORITY\SYSTEM:(I)(F)
                 BUILTIN\Administrators:(I)(F)

C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher>

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C:\Program Files (x86)\Ubisoft>icacls "Ubisoft Game Launcher"
Ubisoft Game Launcher Everyone:(OI)(CI)(F)
                      NT SERVICE\TrustedInstaller:(I)(F)
                      NT SERVICE\TrustedInstaller:(I)(CI)(IO)(F)
                      NT AUTHORITY\SYSTEM:(I)(F)
                      NT AUTHORITY\SYSTEM:(I)(OI)(CI)(IO)(F)
                      BUILTIN\Administrators:(I)(F)
                      BUILTIN\Administrators:(I)(OI)(CI)(IO)(F)
                      BUILTIN\Users:(I)(RX)
                      BUILTIN\Users:(I)(OI)(CI)(IO)(GR,GE)
                      CREATOR OWNER:(I)(OI)(CI)(IO)(F)

Successfully processed 1 files; Failed processing 0 files

C:\Program Files (x86)\Ubisoft>

=======================================================================
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Changed permissions (vendor fix):
---------------------------------

C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher>cacls Uplay.exe
C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher\Uplay.exe BUILTIN\Users:(ID)(special access:)
                                                                                 DELETE
                                                                                 READ_CONTROL
                                                                                 WRITE_DAC
                                                                                 WRITE_OWNER
                                                                                 STANDARD_RIGHTS_REQUIRED
                                                                                 FILE_READ_DATA
                                                                                 FILE_WRITE_DATA
                                                                                 FILE_APPEND_DATA
                                                                                 FILE_READ_EA
                                                                                 FILE_WRITE_EA
                                                                                 FILE_EXECUTE

                                                               NT AUTHORITY\SYSTEM:(ID)F
                                                               BUILTIN\Administrators:(ID)F
                                                               BUILTIN\Users:(ID)R
                                                               labpc\user4dmin:(ID)F


C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher>

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