Multiple untrusted search path vulnerabilities in the installer in Synology Cloud Station Backup before 4.2.5-4396 on Windows allow local attackers to execute arbitrary code and conduct DLL hijacking attacks via a Trojan horse (1) shfolder.dll, (2) ntmarta.dll, (3) secur32.dll or (4) dwmapi.dll file in the current working directory.
The application searches for critical resources using an externally-supplied search path that can point to resources that are not under the application’s direct control.
This might allow attackers to execute their own programs, access unauthorized data files, or modify configuration in unexpected ways. If the application uses a search path to locate critical resources such as programs, then an attacker could modify that search path to point to a malicious program, which the targeted application would then execute. The problem extends to any type of critical resource that the application trusts. Some of the most common variants of untrusted search path are: