Virus Top 10: Zafi.D gives users an unhappy Christmas

While most of the world took some well earned time off from sitting in front of a computer in December, virus writers were as hard at work as ever.

The most reported virus last month, according to antivirus firm Sophos, was Zafi.D, first spotted halfway through December and taking over 36 per cent of all virus reports.

The viruses that have dogged computer users most prolifically - and taken the number one position on the virus top 10 - for months, Netsky.P and Zafi.B, were beaten into third and fourth place respectively by the newly released Zafi.B and Sober.I, which first debuted in November.

The new variant of Zafi.D managed to spread so quickly due to its timely packaging - the virus payload was disguised by an HTML or text message that wished the recipient a happy Christmas and disguised the infected attachment as an e-card or joke.

December's chart in full:

1. Zafi.D 36.8 per cent
2. Sober.I 20.7 per cent
3. Netsky.P 15.5 per cent
4. Zafi.B 8.6 per cent
5. Netsky.D 2.8 per cent
6. Netsky.Z 2.5 per cent
7. Bagle.AA 2.0 per cent
8. Netsky.B 1.7 per cent
9. Netsky.AD 1.2 per cent
10. MyDoom.O 1.0 per cent

Others 7.2 per cent