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Eraser, the data destruction utility

 

  • The problems
 
  • The solution
 
Welcome' to the insecure world of file deletion! If you have confidential data and you want to destroy it beyond recovery to prevent hackers or unauthorized people from restoring it, the worse thing you can do is to delete it using the operating system (Windows). Normal deletion is not secure. Why? Because when you delete a file, the operating system does not destroy the file contents from the disk - it only deletes some ‘references’ on the file from some system tables. The file contents remains on disk until another file ‘happens’ to overwrite it. Any software recovery tool can restore the data if it hasn’t been overwritten yet. Hardware recovery tools may even restore overwritten files by analyzing latent magnetic traces.

Problem No 1: Let’s suppose you have a file that contains sensitive information and you want to get rid of it. You can’t delete it because its contents will remain on disk, becoming an easy target for any hacker with a simple disk tool utility.

Problem No 2: The file slack is usually filled with random information that comes from your computer. The information can be a listing of a directory, a part of a password file or other sensitive data from your computer. Unfortunately, any hacker with a simple disk tool utility can restore it.

Problem No 3: The free space on disk usually contains the contents of the files that were previously deleted using standard operating system commands. Some of them were temporary files used by applications; these temporary files were created and deleted without your knowledge. Let’s also take into account the Windows Swap file, the system file used for the virtual memory support. The size of this file changes dynamically, and it can temporarily store the parts of files or other information. You see now that the disk free (empty) space is not at all “empty”: it may contain passwords, financial records, personal files, etc. In short, it contains sensitive data that can be restored using any disk tool utility.

  Eraser is THE solution to these problems. Its main task is to protect your privacy and prevent sensitive data from falling into the wrong hands. Its main task is to destroy data beyond recovery.

Eraser introduces a verb with a new meaning. To erase a file doesn’t mean anymore just to delete some 'reference' on the file from some system tables and to leave the file sensitive contents lying around on disk waiting for a disk tool utility to recover it. To erase means now three things at the same time: means wiping (overwriting) the file contents to make sure it’s gone and cannot be recovered; means scrambling the file properties (name and dates) in order to remove any clue that might reveal the identity of the erased file; means deleting the file thus removing it form disk (as a normal delete would do).

Wiping is obviously a very, very useful feature. It is the only way to destroy beyond recovery the most important part of a file: its contents. Eraser offers you full control over its wiping features. You can choose between over six standard wipe methods (normal, against hardware recovery tools, etc.) or you can create your own wipe methods. Eraser can overwrite the file contents with fixed, text or random patterns (you can overwrite sensitive data with something like “Censored by Me!”, with zeroes or other fixed patterns or with random letters or digits, etc.)

Scrambling (destroying) the file properties (especially the name) is also a very useful feature. The “Here I kept my passwords” folder or the “My love affair with Lady X Log” file will be renamed to randomly generated names such as F34D2108. Who would guess what the file/folder used to contain? The file dates will be set to 1/1/1980 00:00:00. Indeed all the clues that might reveal the identity of the erased file are now gone.

Truncating the file size to zero and deleting it simply completes the erase task. The file is now GONE FOREVER!

 
  • Capabilities
 
Although the main feature of Eraser is the destruction of files beyond recovery, Eraser can also erase folder structures (folders with all their subfolders and files), it can wipe the slack portion of files (without modifying the files themselves) and it can wipe the free space on any drive. Features like the possibility of collecting multiple file specifications (e.g. *.tmp) turn Eraser into a clean-up utility. The command line parameters allow you to insert erasing/wiping commands to your BAT files and then run this BAT file automatically using Windows 95 SystemAgent or other scheduling software.
 
  • Eraser meets the U.S DoD requirements
 
The US Department of Defense (DoD) has approved overwriting for purging data. The Computer Security Center has issued A Guide to Understanding Data Remanence in Automated Information Systems (NCSC-TG-025) that explains the requirements for overwriting. Eraser was designed to allow you to meet and exceed these specifications.
 
  • The interface
 
Eraser has a very intuitive and easy to use interface. The main window features a list box that contains the names and all the other properties of the files and folders you are going to erase. You can sort the list on any field (by name, type, size, date, attribute, etc.). Adding files and folders to the main list box is very easy: you can drag them from Explorer or you can use the standard Add File and Add Folder dialog boxes. The Add More Files dialog box allow you to add multiple file specifications to the list (e.g. *.tmp, *.bak). Because the files and folders to be erased are first added to the main list box, you can review all your choices before starting to erase.  
Eraser Interface
 

 


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