PACSgear MediaWriter 5.2.1 exposes a .NET Remoting TCP service on port 9000 via PacsgearMediaServerEngine.dll, registered with ObjectURIs RemoteObj and UIRemoteObj, without any authentication requirement. By exploiting the MarshalByRefObject object unmarshalling technique and implementing .NET WebClient class methods, an unauthenticated remote attacker can read and write arbitrary files on the host filesystem. The ObjectURIs are identical across all installations by default. Chaining the arbitrary file write primitive with DLL hijacking opportunities in the MediaWriter service (which runs as NT Authority\\SYSTEM and loads missing DLLs such as CRYPTBASE.DLL from the application directory) enables unauthenticated remote code execution as SYSTEM upon service restart.

PACSgear PACS Scan 5.2.1 contains an unauthenticated remote code execution vulnerability that allows remote attackers to read and write arbitrary files by exploiting an exposed .NET Remoting TCP service on port 22222 via PGImageExchQueue.exe without any authentication requirement. Attackers can chain the arbitrary file write primitive with DLL hijacking in PGImageExchangeQueueSvc.exe, which loads missing DLLs such as CRYPTSP.DLL from the application directory, to achieve remote code execution as NT Authority\SYSTEM upon service restart.