A crypto miner virus, or cryptojacking malware, secretly uses a device’s CPU or GPU to mine cryptocurrency for an attacker, leading to increased electricity costs and potential hardware damage for the victim. It typically infects devices through phishing emails, pirated software, compromised websites, and malicious browser extensions. Monero is the preferred cryptocurrency for mining due to its efficiency on standard CPUs and privacy features. Signs of infection include overheating, high CPU usage, and increased electricity bills. Detection involves monitoring system performance and running antivirus scans. Prevention includes using antivirus software, keeping systems updated, and avoiding pirated software. Notable incidents include attacks on a European water utility and the Los Angeles Times website.