McAfee Labs researchers have discovered new Russian malware, dubbed WebCobra, which harnesses victims’ computing power to mine for cryptocurrencies. Coin mining malware is difficult to detect. Once a machine is compromised, a malicious app runs silently in the background with just one sign: performance degradation.

As the malware increases power consumption, the machine slows down, leaving the owner with a headache and an unwelcome bill, as the energy it takes to mine a single bitcoin can cost from $531 to $26,170, according to a recent report. The increase in the value of cryptocurrencies has inspired cybercriminals to employ malware that steals machine resources to mine crypto coins without the victims’ consent.

The main dropper is a Microsoft installer that checks the running environment. On x86 systems, it injects Cryptonight miner code into a running process and launches a process monitor. On x64 systems, it checks the GPU configuration and downloads and executes Claymore’s Zcash miner from a remote server. The program checks the running environment to launch the proper miner.