Virus writers are changing tactics

Sophos ’security report for May reveals a further decline in the number of worms spreading in emails last month, due to a change in tactics by virus writers.

Sophos has compiled its May safety report based on statistics from its global monitoring networks. This not only reveals a top list of viruses, but we can also notice a number of interesting trends. Most importantly, the number of worms spreading via email continued to decline last month. While a year earlier, every 35th email was infected, in May of this year, only every 141st email had any malware detected. However, security experts warn that this does not mean that the age of viruses is over and that you do not have to worry about virus protection, as there is a significant rearrangement in malware. Virus writers tend to focus on creating more financially promising Trojans, so worms that cause global virus outbreaks are pushed into the background a bit.

Sophos discovered 1538 new viruses last month. 85,1 percent of these were some kind of Trojan program, and "only" 12,3 percent were worms that spread mostly in emails. Netsky-P, which appeared on the Internet in May 2004 and has been causing serious problems ever since, remains at the top of the Sophos virus list. The worm was responsible for 16,7 percent of all virus infections in May. From the top list, it is also worth highlighting the Mytob worm, five different variants of which have entered the ranking list of viruses.

The May top list of viruses was as follows:
1. W32 / Netsky-P - 16.7%
2. W32 / Zafi-B - 1.4%
3. W32 / Nyxem-D - 7.5%
4. W32 / Mytob-AS - 6.3%
5. W32 / Mytob-P - 5.3%
6. W32 / Mytob-M - 5.3%
7. W32 / Netsky-D - 3.7%
8. W32 / MyDoom-O - 3.6%
9. W32 / Mytob-FO - 2.9%
10. W32 / Mytob-C - 2.1%