Virus protection promise sparks a spat

A UK virus-scanning company is offering customers a 100 per cent virus protection guarantee, sparking a debate as to where best to block viruses - on the desktop or on the net.

MessageLabs provides an email filtering system for customers such as the Bank of England, Vodafone and 3i. This passes the emails through MessageLabs servers, which are equipped with virus scanners from McAfee, Vfind and Fsecure as well as its own knowledge-based Skeptic.

Jow White, sales director for MessageLabs, said: "Essentially, we filter the water. Our commercial scanners are updated every ten minutes and Skeptic will pick up any new virus following established patterns.

It also detects virus-like activities. Viruses have to replicate quickly to be effective and they have a pattern of behaviour. The place to stop them is when they're on the net."

But traditional virus scanners disagree. Both Eric Chien, chief researcher at Symantec, and Graham Cluley, senior technical consultant at Sophos, think that it must be stopped at the desktop.

Cluley said: "More and more companies are turning to encryption. The EU last month advised them to do so. Encrypted viruses can't be detected, you have to hit them on the desktop when they are decrypted.

"Trying to get them on the net will involve a loss of security for customers - giving up their private keys- and involves the sort of trawling through emails that most customers won't be comfortable with. There is a place for net filtering, but it's not a replacement for scanning on the desktop."

White pointed out that few emails are currently encrypted and that, if they were, viruses would only spread very slowly.