Troubleshooting and Evasion Detection

Users may attempt to disable, clear, or manipulate Prefetch data to hide their tracks. Awareness of these techniques is key:

• Prefetch Disabled (Registry): The primary control is the EnablePrefetcher DWORD value in the registry at: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters Common values are 0 (Disabled), 1 (Application launch prefetching enabled), 2 (Boot prefetching enabled), 3 (Both enabled - default). A value of 0 found during a check is suspicious and indicates deliberate disabling.

• SysMain Service Stopped: The sysmain service (formerly Superfetch) is responsible for managing the Prefetcher. Check its status using sc query sysmain in an administrative CMD. If the service STATE is not RUNNING (e.g., STOPPED), Prefetching is inactive. Restarting the service might be necessary for logging to resume, but doing so also clears some volatile system caches, which can impact other analysis steps. Finding it stopped without good reason is a red flag.

• Permission Tampering (CACLS/ICACLS Bypass): Attackers might alter the security permissions (ACLs) of the C:\Windows\Prefetch folder itself to prevent the System or SysMain service from writing new .pf files or updating existing ones. This can be done using commands like cacls or icacls. Check the folder's Security tab in its Properties. Evidence of recent permission changes (granting/denying write access) can often be found in the USN Journal ($UsnJrnl) by looking for SECURITY_CHANGE reason codes associated with the Prefetch directory path.

• Hidden Prefetch Files: Individual .pf files can be marked with the 'Hidden' attribute. Use dir /ah C:\Windows\Prefetch in an administrative CMD to reveal any hidden files within the directory.

• Prefetch Clearing: Users may simply delete the contents of the C:\Windows\Prefetch folder. Finding the folder empty or missing expected entries (like .pf files for explorer.exe, AnyDesk.exe, or the game itself) when the SysMain service is running and Prefetch is enabled in the registry is highly indicative of manual clearing. The USN Journal ($UsnJrnl) is the primary tool to detect this, as it will log numerous FILE_DELETE events corresponding to .pf filenames occurring around the time of the clearing.