3,500 Websites Hijacked to Secretly Mine Crypto Using Stealth JavaScript and WebSocket Tactics

A new attack campaign has compromised more than 3,500 websites worldwide with JavaScript cryptocurrency miners, marking the return of browser-based cryptojacking attacks once popularized by the likes of CoinHive.

Although the service has since shuttered after browser makers took steps to ban miner-related apps and add-ons, researchers from the c/side said they found evidence of a stealthy miner packed within obfuscated JavaScript that assesses the computational power of a device and spawns background Web Workers to execute mining tasks in parallel without raising any alarm.