November breaks all malware records

Trojan software either logs the user's behaviour or allows remote control of their PC

November was the worst month for malware since records began in the mid-1980s, according to antivirus firm Sophos.

The company detected 1,940 new pieces of malware in the past month, and has seen a 48 per cent increase in threats over the year.

The bulk of the new threats are not self-propagating viruses such as worms, but Trojan software that either logs the user's behaviour or allows remote control of their PC.

"A worm affects too many people these days," said Graham Cluley, senior technology consultant at Sophos. "It draws attention to them and encourages antivirus firms to take action. It also brings in a flood of information that the hacker cannot cope with."

Cluley explained that the recent figures also show the extent to which organised criminals have started using malware for financial gain.

In terms of using malware-gathered information for banking fraud, for example, it is easier to steal money from 200 people than 200,000.

While self-propagating viruses are still in circulation they are predominantly older viruses. Zafi-D, the year's most common virus, will be a year old on 14 December and a cure is available in all antivirus software packages.

The exception to this was the recent Sober worm which, had it been released before November, would quickly have become the biggest virus of the year. 

These viruses are most common on home computers rather than enterprise systems. Cluley warned that many home users seldom or never update their security software and so act as reservoirs of infection that infect others.

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