Increasingly desperate to cash in on the sky-rocketing price of Bitcoin these days, gangs of cybercriminals have designed a new malware that’s infecting computers via Skype in an attempt to build a botnet massive enough to start mining the virtual currency.

The malware was unearthed late last week by researchers at Kaspersky Labs, who discovered that its creators had used it to seize control of hundreds of computers in Russia, Germany, Ukraine, Poland, Spain and other countries.

It spreads itself by infecting the Skype VoIP program, using the age old trick of sending messages to an infected user’s contacts, such as “Hey, this is my favorite picture of you”, alongside a link to a malicious download. Should the unwitting victim click on that link, the malware downloads itself onto their PC, press-ganging the machine into a becoming a Bitcoin mining slave alongside the rest of its botnet.

Bitcoin mining malware is just the latest tactic we’ve seen from cybercriminals that are presumably very keen to step up their abuse of how the virtual currency works, given its record high value of late. Previous tactics have included malware designed to target people’s Bitcoin wallets, while there have also been a number of high-profile hacks of Bitcoin exchanges that have resulted in the loss of thousands of dollars’ worth of online readies. More recently we have seen attacks on payment services like Dwolla, which provides one of the main ways to buy Bitcoin on Mt Gox, and last week’s Instawallet heist, which saw hackers gain access to the personal accounts of an unknown number of users.

The latest malware targets the way in which Bitcoin is created – “miners” work to solve cryptographic problems called Bitcoin blocks in order to create new Bitcoins whenever they’re required. Solving these problems requires massive computing power and the work can take several hours (hence, the more computers at your disposal, the faster the problem can be solved), earning miners a number of Bitcoins for each block solved as a reward for their endeavors.

These rewards are no small change either, according to one estimate. Back in 2011, when the Bitcoin was worth a ‘mere’ $20, Symantec estimated that a botnet numbering some 100,000 computers could pull in something in the region of $3,000 a day – not a bad return for spreading a simple piece of malware around the net.

Of course, these days the Bitcoin is trading at prices far higher than 2011. On Mt. Gox today, it’s been hovering around the $180 mark for the last 24 hours or so, meaning that if Symantec is right anyone with a 100,000 strong botnet could conceivably rake in $27,000 a day – which is a serious amount of money by anyone’s standards.