XP file destruction sparks controversy

The data destruction feature in Windows XP promises to permanently remove data from the hard disk, but data recovery specialists say it is not up to scratch.

Having a universally available data destruction tool has divided security experts into those who call it a threat to national security, and those who say it is "the first right thing Microsoft ever did".

Neil Barrett, technical director at Information Risk Management, stressed that network managers have a genuine and legitimate reason to permanently erase data from their network - computer thefts and disposal warrants it.

Legislation such as the Data Protection and Human Rights Acts rule that personal data should not be kept for longer than necessary.

"Inserting a secure deletion tool in the OS sounds like an appropriate thing to do," Barrett said. "But we need proof it works. You only have to think of IIS to know you can expect teething problems."

Gordon Stevenson, managing director of data recovery company Vogon International, said XP's secure deletion feature was more sophisticated than third-party erasing software because it was embedded in the OS. But he warned that the way hard disks work makes it impossible for software to erase all the data.

As a hard disk gets worn in, physical errors occur in its sectors. The drive internally re-maps damaged sectors to other parts of the disk and never uses the area again.

But this is a physical level decision made by a drive and data destruction software cannot tell it is happening. The software writes over the disk, but even a secure wipe will miss these 'damaged' sectors. Data from these areas can easily be recovered in a proper lab.

"You cannot use software to destroy data on a disk. The only way is to physically destroy it," said Stevenson. "We have recovered sensitive data from disks treated with erasing software."

Across the Atlantic, concerns about how terrorists might exploit a data destruction tool has sparked a debate over whether the feature should be included in XP.

Michael Anderson, retired US federal agent turned forensic expert, urged the US Government to force Microsoft to postpone the launch of Windows XP Professional in light of the 11 September attack.

Anderson provides computer forensics training to the US military and law enforcement agencies and argued the feature would "slam the door on all forensic work".

He believes that putting data destruction software in Windows XP would make the tool too widely available to terrorists.

In addition, Chuch Guzis, president of data conversion software company Sydex, wrote to Congress to ask it to postpone the launch, because "we don't have the tools or methodology to combat XP".

But UK digital forensic experts argue that a feature to permanently remove data from hard disks, serves an important role of removing data from computer networks.

Barrett often works with police forces to assemble digital forensic evidence in computer crime investigations. He said the recovery of deleted files is useful but not essential in criminal investigations.

He argued that before a raid, police officers should work with ISPs to collect evidence on suspected individuals.

"Permanently erasing files from hard disks will make our job more difficult, but it was never said that it should be easy. Some have said that data destruction will bring civilisation to its knees, at the mercy of paedophiles and international terrorists - but that is just hilarious, he said."