Few take time to erase hard drives
By Justin Pope
Associated Press
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| Simson Garfinkel, a graduate student at MIT's Laboratory for Computer Science, and a fellow student analyzed secondhand computers that had functional hard drives and found some recoverable files, many of which contained personal and financial data from the previous owners.
Associated Press |
A pair of MIT graduate students suggest you think again.
Over two years, Simson Garfinkel and Abhi Shelat assembled a collection of 158 used hard drives, shelling out between $5 and $30 for each at secondhand computer stores and on eBay.
Of the 129 drives that functioned, 69 still had recoverable files on them and 49 contained "significant personal information" — medical correspondence, love letters, pornography and 5,000 credit-card numbers. One even had a year's worth of transactions with account numbers from an ATM in Illinois.
"On that drive, they hadn't even formatted it," Garfinkel said. "They just pulled it out and sold it."
About 150,000 hard drives were "retired" last year, the research firm Gartner Dataquest estimates. Many ended up in trash heaps, but many also find their way to secondary markets.
Over the years, stories have occasionally surfaced about personal information turning up on used hard drives that have raised concerns about personal privacy and identity theft risks.
Last spring, the state of Pennsylvania sold to local resellers computers that contained information about state employees. In 1997, a Nevada woman purchased a used computer and discovered it contained prescription records on 2,000 customers of an Arizona pharmacy.
Garfinkel and Shelat report their findings in an article in the journal IEEE Security & Privacy.
On common operating systems such as Unix variants and Microsoft's Windows family, simply deleting a file, or even following that up by emptying the "trash" folder, doesn't necessarily make the information irretrievable.
Those commands generally delete a file's name from the directory, so it won't show up when the files are listed. But the information itself can live on until it is overwritten by new files.
Even formatting a drive may not do it. Fifty-one of the 129 working drives the authors acquired had been formatted but 19 of them still contained recoverable data.
The only sure way to erase a hard drive is to "squeeze" it: writing over the old information with new data — all zeros, for instance — at least once but preferably several times.
A one-line command will do that for Unix users, and for others, inexpensive software from companies including AccessData works well.
But few people go to the trouble.
What really strikes Garfinkel is how many people he found bidding for old drives on eBay. He shudders to think what they want with them.
"If I were a government interested in doing economic espionage against the United States, I would allocate a million dollars a year to buy these hard drives and analyze them," he said.
In fact, it wouldn't even take that — just somebody willing to hold their nose and walk around the municipal dump.
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