Virus Top 10: Writers stayed Sober this Christmas

While harassed Christmas shoppers were busy getting in the last minute gifts, virus writers were equally hard at work churning out malicious code in time for the festive season. But, like the Christmas top 40, the big hitter that topped charts in the world of malware this month was a new take on an old classic.

December's statistics from antivirus company Sophos showed the most reported virus this month was Sober-C, making up 23.3 per cent of all malware. While a relative newcomer to the scene – Sober-C was only found in the wild on 21 December last year – a previous variant of the Sober worm made first place last month.

The virus is spread over email and P2P networks, but can be hard to identify as the email which carries it has a variety of subject lines, from the friendly - 'Thank You very very very much' - to the less than complimentary - 'you are an idiot'.

While Sober-C clocks up the most incidences for a single virus, Mimail put in a strong showing, with 29.7 per cent of all reported malware being a version of the virus, with the K, J, C and F variants all making the top 10.

Nevertheless, virus writers weren't short of imagination this Christmas, it seems. Carole Thierault, security consultant at Sophos said in a statement: "With more than 700 new viruses arriving in our lab during December, it's fair to say that virus writers were not interested in taking a break over the festive period."

While this month's virus chart might be giving users a case of déjà vu, it could be all change in January – with Sophos' own antivirus mouthpiece, Graham Cluley, the star. He's the subject of virus called Quis supposedly developed by Belgian writer Gigabyte, which poses a serious of questions along the lines of "what does antivirus person Graham Cluley have between his toes?" - which, if answered correctly (cheese, apparently), directs users to a site with details of how to disinfect their machines.

December's chart in full:

1. Sober-C 23.3 per cent

2. Mimail-K 21.3 per cent

3. Dumaru-A 13.8 per cent

4. Mimail-J 2.7 per cent

5. Mimail-C 2.2 per cent

6= Gibe-F 1.9 per cent

6= Mimail-I 1.9 per cent

8. Klez-H 1.8 per cent

9= Torvil-A 1.6 per cent

9= Mimail-F 1.6 per cent

Others 27.9 per cent