"The basic idea behind mining is easy enough: if you have powerful computers, you can make money," Hypponen says, but adds, "unfortunately, those computers don't have to be your computers."
In analysing malware, F-Secure has found that infected computers taken over by cybercrimals can also be commandeered to make Bitcoins, and that's what has happened in some instances.
There has been a rise in the first half of the year in several types of malware targeting Bitcoin, and a botnet based on the ZeroAccess family of malware includes a powerful rootkit to hide its presence. F-Secure has spotted a large ZeroAccess botnet operator running a Bitcoin mining operation with various plug-ins on infected PCs. "We estimate them to be make over $50,000 a day by mining Bitcoins on infected computers," Hypponen says. "If such operations are already happening today, it's easy to see that mining botnets will become very popular for online criminals in the future."
Sign up for CIO Asia eNewsletters.