On-access scanning and how it works

The on-access scanner hooks into the system at the lowest levels (File-System Filter Driver), acts as part of the system (System Service), and delivers notifications via the interface when detections occur.

This example describes what happens when an attempt is made to open, close, or rename a file. The scanner intercepts the operation and takes these actions.

1. The scanner determines if the file should be scanned based on this criteria:
   
   • The file’s extension matches the configuration.
   • The file has not been cached.
   • The file has not been excluded.
   • The file has not been previously scanned.
2. If the file meets the scanning criteria, it is scanned:
   
   • If the file is clean, the result is cached and read, write, or rename operation is granted.
   • If the file contains a threat, the operation is denied and the configured action is taken.
   • The results are recorded in the activity log if the scanner was configured to do so.
3. If the file does not meet the scanning requirements, it is not scanned. It is cached and the operation is granted.