Spam e-mails are on the rise again following a brief reprieve over the Christmas period when the number of malicious mails sent dipped below 50 billion.
Leading the way is the Rustock botnet, which got back to business yesterday after an apparent shut-down from early December that contributed to an overall decline in spam e-mails, the BBC reports.
The number of spam mails sent fell to 30 billion by late December, figures from Symantec show.
However, the firm says the Rustock network popped up on its radar again yesterday, and is already generating a quarter of global spam e-mail traffic, with around 67 billion messages sent.
Symantec analyst Paul Wood told the BBC the dip in activity was likely due to Rustock’s owners renting the network to another group during December, and dismissed speculation the operators simply took a break for Christmas.
Despite the ramp in messages generated by the botnet, Wood said it was too early to predict if the level would get back to the high of 200 billion messages seen at the network’s peak in August.
Rival security firm NetWitness also noted the return of Rustock, but suggested the seasonal dip could have been due to the operators taking a vacation over the festive period, the BBC said.