Serviio PRO 1.8 DLNA Media Streaming Server Local Privilege Escalation Vendor: Petr Nejedly | Six Lines Ltd Product web page: http://www.serviio.org Affected version: 1.8.0.0 PRO Summary: Serviio is a free media server. It allows you to stream your media files (music, video or images) to renderer devices (e.g. a TV set, Bluray player, games console or mobile phone) on your connected home network. Desc: The application suffers from an unquoted search path issue impacting the service 'Serviio' for Windows deployed as part of Serviio DLNA server solution. This could potentially allow an authorized but non-privileged local user to execute arbitrary code with elevated privileges on the system. A successful attempt would require the local user to be able to insert their code in the system root path undetected by the OS or other security applications where it could potentially be executed during application startup or reboot. If successful, the local useras code would execute with the elevated privileges of the application. Serviio also suffers from improper permissions which can be used by a simple authenticated 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 'Users' group, for the Serviio directory and its sub-directories. Tested on: Microsoft Windows 7 Professional SP1 (EN) Microsoft Windows 7 Ultimate SP1 (EN) Vulnerability discovered by Gjoko 'LiquidWorm' Krstic @zeroscience Advisory ID: ZSL-2017-5405 Advisory URL: http://www.zeroscience.mk/en/vulnerability/ZSL-2017-5405.php SSD Advisory: https://blogs.securiteam.com/index.php/archives/3094 12.12.2016 --- C:\>sc qc Serviio [SC] QueryServiceConfig SUCCESS SERVICE_NAME: Serviio TYPE : 110 WIN32_OWN_PROCESS (interactive) START_TYPE : 2 AUTO_START ERROR_CONTROL : 1 NORMAL BINARY_PATH_NAME : C:\Program Files\Serviio\bin\ServiioService.exe LOAD_ORDER_GROUP : TAG : 0 DISPLAY_NAME : Serviio DEPENDENCIES : HTTP SERVICE_START_NAME : LocalSystem C:\>icacls "C:\Program Files\Serviio\bin\ServiioService.exe" C:\Program Files\Serviio\bin\ServiioService.exe BUILTIN\Users:(I)(F) NT AUTHORITY\SYSTEM:(I)(F) BUILTIN\Administrators:(I)(F) Successfully processed 1 files; Failed processing 0 files C:\>