The move to more targeted Trojan attacks as opposed to mass mailing worms left last month's virus charts almost static.
The long running Netsky-P worm continues to top Sophos's anti-virus charts, with the top five most prevalent pieces of malware retaining their position from August. There were no new entries in September's chart and just one re-entry - MyDoom-AJ.
The overall proportion of infected email has dropped to an all time low of just one in 300 (0.33 per cent), Sophos reports. But the move from mass mailing in favour of more subtle and menacing Trojan assaults, targeted at just a small group of users, meant the number of new threats shot up. Sophos recorded 4,080 new threats in September, compared with just 1,998 in August 2006.
Russian anti-virus firm Kaspersky Labs backs Sophos's conclusion that there's a move away from global epidemics towards smaller, more low-key attacks. However, it rates Nyxem-E as its top reported threat with Mytob-C (seventh in the Sophos chart) as number two in Kaspersky's rogues gallery.
September 2006 malware chart, according to Sophos
- MyDoom-AJ (re-entry)