McAfee's Avert Labs operation says that 12 million new IP addresses - almost certainly representing many, if not more, infected computers - were identified during the first quarter of 2009 as having a `zombie' PCs connected to them.
In a video interview with the VNUnet newswire, Jeff Green, head of McAfee's Avert Labs, says that the problem stems from botnets being reseeded by operators.
According to Green, he expects to see a surge in spam on the back of these botnet reseeds later this year.
Interestingly, McAfee says it has observed the market for stolen data is also changing, with some criminals preferring to steal bank account information and, rather than use them within their own criminal gangs, sell the data on for a quick profit.
And the number of malware variants is also rising, says McAfee, which keeps copies of all the infections etc., its staff come across in a `virus zoo.' In Q1 of 2009, the company added four million items to its zoo, it says.