Kessler International, a computer forensics company from New York, conducted a study of used hard drives available on eBay. Almost half of the hundred drives they sampled, purchased in random bulk lots, contained data that was easily recovered. A shocking amount of them required no more recovery effort than plugging them in and powering up. They found personal photos, financial records, emails, personal and corporate correspondence, corporate secrets, and more:
“The average person who knows anything about computers could plug in these disks and just go surfing,” Kessler said. “I know they found a guy’s foot fetish on one disk. He’d been downloading loads and loads of stuff on feet. With what we got on that disk — his name, address and all of his contacts — it would have been extremely embarrassing if we were somebody who wanted to blackmail him.”
While you may not be particularly worried about the world finding out about your curious interest in Manolo Blahniks, nobody should run the risk of their personal and financial data leaking into the wild when it is so easily prevented. Photo by makani5.
Understanding File Deletion
There are several methods for securely deleting files from your disks. Institutions like the Department of Defence, universities, and law enforcement agencies have created standards for what they would consider adequate scrambling of sensitive disk data. We’ve recommended some tools over the years that cut the same profile, or close to, their methods. Below is a list of tools, arranged by severity and operating system:
Total Disk Wipe – All Platforms
Darik’s Boot and Nuke – an open-source boot disk utility (read: works on nearly any computer) that supports a wide variety of disk wiping methods and operates from inside the computer’s RAM, allowing it to scrub the disk thoroughly at a remove.
Selective File Wipe – Windows
Wipe File – Portable application that overwrites the specific disk space occupied by the file you’d like erased and leaves the rest of the disk untouched.
DeleteOnClick – Integrates with the Windows shell, adding a “Securely Delete” option to the right click menu which engages a Department of Defence 5220.22-M overwrite on the files.
Eraser – In addition to securely deleting individual files, Eraser can be scheduled to perform regular overwrites of empty disc space ensuring you catch those orphan files hanging outside the reach of Windows.
Selective File Wipe – Mac OS X
Permanent Eraser – Although Mac users have had the “secure empty trash” option, based on a multiple pass DoD method, since OS 10.3, Permanent Eraser offers peace of mind for those needing more assurance.
You can never be too vigilant with your data. The amount of effort it takes to securely wipe a disk or decommission an old disc by physically destroying it pales in comparison to the time and headaches you’ll burn through undoing the damage of identity theft—or worse. If you have a technique or handy piece of software not mentioned here, please share in the comments below to help your fellow readers keep their data secure.
Jason Fitzpatrick is the Weekend Editor for Lifehacker and all around paranoid about data security. On his watch, many a hard drive has been retired with a rifle crack.