An innovative botnet was using Twitter to control "mining" operations for the Bitcoin virtual currency.
"Botnet masters use other people's computers to mine Bitcoins for them," said chief research officer for F-Secure, Mikko Hypponen, in a blog post.
He said incentives were offered to create botnets because Bitcoin could be mined by solving difficult cryptographic proof-of-work calculations and then exchanged for cash.
It was identified as Trojan . Generic . KD.
But Symantec researcher Peter Coogan said in June it could be put to more profitable use: "Bitcoin botnet mining as an attractive and profitable venture for cybercriminals is very questionable," he said.
He compared the income for using such a botnet to rent on the underground market.
It said the "usual offer" for the hire of a good botnet was about $400 a week for a few hours a day.