The company's Avert Labs identified 12 million new IP addresses in the first quarter of 2009 as belonging to 'zombie' PCs, infected machines used remotely in botnets.
"This is the reseeding of botnets," Jeff Green, head of McAfee Avert Labs, said in a video interview with vnunet.com. "We are expecting an uptake in the amount of spam later this year as a result."
Malware variations are also on the rise, according to Green. McAfee keeps a copy of every piece of malware it encounters in a "virus zoo", and had added four million new samples in the most recent quarter.
Avert Labs also saw a sharp rise in the levels of malware in circulation during 2008, reporting growth rates of 270 per cent. So far this year the rate has grown by 115 per cent.
"When I got the figures I sent my team back and told them to do the calculations again," he said. "I thought they'd been smoking something. We're seeing a phenomenal growth rate."
The market for stolen information is also changing, Green said. Some data thieves prefer to steal bank account details and sell them on rather than use the data themselves.
Green gave the example of a Washington Mutual bank account containing $14,400 (£8,730) that was recently put on sale for $924 (£560). In some cases, the sales are backed by a guarantee of access.
Gamers are also being targeted. The growth in games that allow players to trade online goods makes them a tempting target for criminals, and the situation is not helped by gamers turning off security software to increase system speed.
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