Virus experts have declared Macs to be safe – yet not immune – to viruses as they consider the mass virus attacks that blighted computer users in August.

Mac users face just 50 recognized viruses today, while PC users have 85,000 threats to their security. London-based firm mi2g says: "Mac customers running Mac OS X, an implementation of BSD, benefit from BSD's proven reputation as being one of the most secure operating systems available."

Sophos Anti-Virus senior technology consultant Graham Cluley warned against complacency: "Mac users shouldn't be complacent, although there are far fewer viruses for Mac than PC, they do still exist, but are just not being written in the same numbers. Mac users are lucky, but should not think they are invulnerable to virus attack," he told Macworld.

'Macs for security' - Zeiler

Writing for Sunspot.Net, columnist David Zeiler believes governments should adopt Macs as part of their defence against virus attacks. He points to the Office of Management and Budgets addition of Mac OS X and Linux to its Technical Reference Model this month, and Apple CFO Fred Anderson's comments that Apple's sales to federal agencies were up over 60 per cent in each of the last two fiscal years. Mac OS X furnishes a line of defence, his argument runs.

"Virus writers focus on Windows for a number of reasons. It's the dominant OS – one of the main motives of virus writing seems to be to infect as many computers as possible, so targeting Windows rather than Mac makes sense; also there are more viruses in existence that can act as a blueprint for virus writers," he said.

August was 'the cruellest month' Steven Sundermeier of Central Command Inc. called August 2003 "one of the worst computer virus related months in recent memory." He revealed that at one point the anti-virus firm saw that 70 per cent of all email being Sobig.F-related.

"We have not seen a high-impact Mac virus in a very long time," he said. Sundermeier echoed Cluley's thoughts, adding: "I believe virus creators like to infect the masses to see how many users they can infect at once, so they focus on Windows," he told me.

But Mac users have a part to play, he said: "Mac users can still receive infected email and forward this to others running Windows, thus acting as a conduit for infection."

There are other forms of suffering, Cluley added: "I know of one Mac user who reported receiving over 6,000 instances of the Sobig-F worm in their email."

Mac users may also experience slow Internet connectivity because of the vast number of viral emails clogging email servers.

Security experts agree that Mac users should install and use anti-virus software, if only to avoid passing on viruses to others.