Distributing Bitcoin miner using RAT Botnet
Botnet could be a RAT (remote administration tool) that the hacker spread over the internet by encrypting it and making it FUD (Fully Undetectable) by anti viruses, he can later bind it with any crack or software, and it will become a danger treat, that's why people should not download Crack/keygen or any related applications, for the sake of not only the economy but their security.
A Bitcoin miner is a small command line application that use your processor or GPU to generate Bitcoin hashes then send them to the hacker or a mining pool, a mining pool is a tiny network for the mining bots to join force and generate hashes in a mass form.
After the hacker or the botmaster spread his botnets or trojans over the the internet, getting hundreds of victims (zombie computer) he will later order them all to download and run the Bitcoin mining application passing his username and password for his pool, the victim machines will start generating hashes and making digital currency "Bitcoin" for the Botmaster, the victim computers will be running slow or worst crash, the process of mining usually takes 100% of the CPU or GPU.
There is no way to avoid this but to install a good Firewall like COMODO, and monitor all the traffic, also keeping an eye on any suspected application that runs 100% of your processor.
many people don't care or don't notice the slowness of their machines or they just format it without knowing the reason.
Bitcoin is still not popular or understandable by normal users, most don't even know what is peer-to-peer networks, so how they are spouse to understand peer-to-peer money.