Subject: Disk Scrubbing Tools

Audience: Administration

Date: June 26, 2004
Update: January 2006

Complete removal data from a disk may be required as security precaution when disposing of a disk that contained sensitive information. Standard AIX tools like "rm" or "reducevg" are insufficient as they do not "zero out" the data.

The appropriate AIX 5.2 and 5.3 tool would be the diag -T "format" command This command in AIX 5.2 ML6 meets CAPP-EAL4+ standards. However, prior AIX 5.2 maintenence levels and AIX 5.3 do not. http://www16.boulder.ibm.com/pseries/en_US/infocenter/base/5206_base_relnotes.htm#wq185

A possible alternative is the US DOE tool called "scrub". It's available from
http://www.llnl.gov/linux/scrub/scrub.html

The source is available for compiling on AIX. As a third party tool, it is not supported by IBM.

Update February 2006. Follow-on information

http://www.kyuzz.org/antirez/overwrite.html

Data stored on magnetic disk media can be recovered using sophisticated analysis techniques. This means that, for example, even if some your old file was overwritten by new data, maybe it's still recoverable. Overwrite is a UNIX utility that try to make harder data recovering. What overwrite does is to overwrite files using random patterns and deterministic patterns, as suggested in the Peter Gutmann's paper "Secure Deletion of Data from Magnetic and Solid-State Memory".

Peter Gutmann's paper "Secure Deletion of Data from Magnetic and Solid-State Memory" http://www.cs.auckland.ac.nz/~pgut001/secure_del.html
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This too:
http://www.dss.mil/isec/chapter8.htm
http://www.lat.com/regs.html