Vitalik Buterin, technical editor at Bitcoin Magazine, said the the rise of Asic mining meant cyber-thieves would soon be pushed out.
Currently, he said, only about one-third of all professional miners were using Asics, but as that proportion grew, the number of bitcoins that could be generated with a botnet would shrink.
"The fact that botnets are (somewhat) viable now is basically an aberration resulting from the massive price increase that has not yet been matched by increased mining activity," he said. " Once Bitcoin stabilises again the botnets will rapidly crawl back into the shadows."