Crypto-jacking is when a cyber criminal uses a victim’s computer to mine crypto currency such as Bitcoin. Like all malware, victims could unintentionally click on an email or text message that infects their computer. Programs called “coin miners” are used to mine these crypto currencies and because crypto currency is all digital, only computer programs and power are used.
While only using computer power to mine crypto currency doesn’t seem like much of a threat. The hacker behind it also has control of the computer it is running the coin miner on. They could take personal information or install malware to monitor activity. All this is done for a criminal purpose and without the victim knowing. Hackers can gain huge profits from this, especially if they have a botnet (web of infected devices) Not only does the hacker do this without consent but they also increase electricity costs for the victim as it requires a huge amount of power to mine cryptocurrency.
Obvious signs that your device might be being used for crypto mining can be a slowdown in your device’s performance. Sudden spikes in electricity costs can also be signs of crypto-jacking as crypto mining needs tons of energy. Be sure to monitor device processing speed and energy consumption because it can help indicate whether or not the device is being used for crypto-mining or not.
Source: https://www.interpol.int/en/Crimes/Cybercrime/Cryptojacking