The Blaster worm and the sixth variant of Sobig made August a record month for malicious worm activity, according to security experts.
'August 2003 will be remembered as one of the worst months in the history of computer security,' security firm Sophos claimed in its latest monthly chart of virus activity.
A series of viruses 'bombarded' computer systems around the globe during the month, culminating in the newest member of the Sobig family which 'swamped Internet email traffic and took pole position in the chart' said Graham Cluley, senior technology consultant at Sophos Anti-Virus in a statement.
What is more, the top four viruses for the month are all new entries. Any one of them would have been number one in a normal month, according to Cluley.
The variant on Sobig - Sobig-F - topped the chart, accounting for 37.6 percent of interceptions leaving Blaster behind in second place at 18.8 percent. Nachi and Mimail, also new entrants, followed at 5.5 percent and 5.3 percent respectively.
According to media reports, the teenager accused of developing Blaster - Jeffrey Lee Parson - was arrested and released after being placed on electronic monitoring and ordered not to access the Internet.
