Sasser virus hits systems but fails to do real damage

The 'Sasser' virus, a worm that causes personal computers to shut down and reboot, inflicted damage across the internet yesterday, bringing down systems at banks, British Airways (BA) and the European Commission. Brandon Glenn reports

Although the worm has the potential to infect millions of computers, its effects appear to be little more than an inconvenience to the average user, Internet security experts said.

A worm is a type of virus that replicates itself across computer networks and often uses up memory resources, but does not attach itself to other programs.

The virus, detected last Friday, at first glance appears to be particularly insidious, because, unlike most viruses, it spreads without any human trigger.

However, the virus merely causes infected computers to crash and reboot by attacking a weakness in the Microsoft 2000, XP and NT operating systems, according to Mr Gian Schoeman, a consultant with Dublin-based Unit 4 Aggresso Security Solutions.

"That's fine if you're on a personal computer," said Mr Stephen Rogan of Unit 4, "but if you're a large organisation and it's causing your servers to reboot, it causes productivity issues."

The virus essentially sits on the Internet and scans for vulnerable PCs, instructing unprotected computers to download and execute it.

PCs connected to the Internet without the protection of a firewall, a system that prevents unauthorised access to a network or a PC, are particularly susceptible.

It is difficult to tell the number of PCs affected, although some reports estimated it to be more than one million.

Another factor that obfuscates the virus damage, according to Mr Rogan is that "large companies don't tend to tell you they are hit because it's bad for business to tell you that they're not protected".

A Government spokesman said none of its systems had been affected by the virus.

Mr Simon Perry, vice-president for security strategy at Computer Associates, estimates that about 10 per cent of large businesses had been directly affected by the virus.

"For companies with machines that aren't up to date. It's causing all sorts of problems, from customer-service \ to websites being down," Mr Perry added.

Mr Perry said that the virus had had a "measurable impact on the financial and government sectors".