Technical Review
In-depth, A1RunGuard uses Windows
Image File Execution Debugger method to intercept the running of the executable files.
This technique has a lot of advantages (over other methods/techniques):
- System files are not changed.
- No drivers, complete independence of running executables.
- Perfect compatibility with Windows versions (from Windows 7 to Windows 11).
- Easy set/undo by changing several registry keys.
- Block processes by its name or by full pathname.
However, there are also cons of the said method, which are:
- This technique does not support wildcards in the process names.
- The process is intercepted by the name, not by its contents.
What happens during the launch of an application?
- Windows checks for the presence of the sub-key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\{name of the executable}.
- If the sub-key exists, Windows checks for the "Debugger" registry value.
If this value exists, Windows executes the file, stored in the Debugger value with the command line of the started application.
- A1RunGuard uses its application: "A1RunScanner.exe" as a debugger.
A1runscanner.exe then completes the launch the application or blocks it.