Protecting temporary and system files
During the course of normal operation, Windows and the various applications that run on it are continuously opening and closing temporary files and using memory swap space (the paging file). Windows and these applications often leave important information such as your user data or usernames and passwords in these files, so they need to be protected. When Windows crashes, by default it dumps anything in memory (which can also contain sensitive data) to a "dump file," which is stored on the hard drive in case you need Microsoft to debug your problem. This too needs to be addressed.
In a previous tip, we suggested encrypting the temp folder on Windows 2000 systems, which provides a little protection to the files created by the OS and applications, but only in this one folder. To protect the dump file and paging file, we just need to clean them up. We'll start by completely disabling Windows' ability to create the dump file. You'll probably never use it, and if you do need it, you can always turn it back on, use it, then turn it back off and delete the file.
To disable the dump file, go to the Control Panel and double-click System. Select the advanced tab and click Startup and Recovery. Change the options for 'Write Debugging Information" to None. (You'll need to reboot your system after you make these changes.)
You can't really disable the paging file because your OS and applications need it to function, even if that means they are storing your private information. So to protect the paging file, the best thing to do is simply clear it every time you shut down the computer. This can be accomplished by using the Registry Editor. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management. Inside, you will find a value named ClearPageFileAtShutdown. Change this to a 1.
IMPORTANT: Editing your system's registry is very dangerous. As always, before making changes, be sure to back up your data in the registry, and be sure you know how to restore, in case you mess up.
Thomas Alexander Lancaster IV is a consultant and author with over ten years experience in the networking industry, focused on Internet infrastructure.