Malicious Cryptomining:
Malicious cryptomining, also sometimes called drive-by mining or cryptojacking, is an increasingly prevalent form of malware or browser-based attack that is delivered through multiple attack methods, including malspam, drive-by downloads, and rogue apps and extensions.
It allows someone else to use your computer's CPU or GPU to mine cryptocurrency like Bitcoin or Monero. So instead of letting you cash in on your computer's horsepower, the cryptominers send the collected coins into their own account—not yours. So, essentially, a malicious cryptominer is stealing your device's resources to make money.