Title: Securely deleting files in Linux

KBTAG: kben10000009
URL: http://www.securityportal.com/lskb/10000000/kben10000009.html
Date created: 13/03/2000
Date modified:
Date removed:
Authors(s): Kurt Seifried seifried@securityportal.com
Topic: Programs that let you securely delete files and devices in Linux
Keywords: Filesystem, Users/Data

Summary:

Deleting files does not actually destroy the files, it simply unlinks them. Even if the inode/etc are not known a determined attacker can retrieve files, usually quite easily from your magnetic media. In order to securely "delete" a file it is necessary to overwrite it multiple times with various bit patterns to remove all traces of it.

More information:

Several "secure delete" programs exist for Linux, and the GNU file-utils package should support secure deletion in the near future. They securely delete data by overwriting the file (or device) multiple times with various bit patterns, i.e. all 0’s, then all 1’s, then alternating 1’s and 0’s and so forth. If used on files remember that filename’s, creation dates, permissions and so forth might be recoverable, so make sure you wipe the device if you absolutely must remove all traces of something (or use an encrypted filesystem).

Downloads:

http://www.infowar.co.uk/thc/

http://wipe.sourceforge.net/