Your laptop fan roars for no reason, the battery drains fast, and everything feels sluggish — yet you are barely doing anything. One possible culprit is cryptojacking: hidden code quietly using your device to mine cryptocurrency for someone else, at your expense. Our GetMyPassword team explains what cryptojacking is and how to stop it.
What cryptojacking is
Cryptojacking is the unauthorized use of your device’s computing power to mine cryptocurrency. Mining is profitable but requires a lot of processing, so attackers steal it by running hidden mining code on other people’s machines. It reaches you through a malicious download or app, or through a compromised or sketchy website that runs a script in your browser while the page is open. You get none of the coins; you only pay the cost — in slower performance, higher electricity use, and wear on your hardware. Unlike many attacks, the goal is not to steal your data but to quietly borrow your resources, which is why it can run unnoticed for a long time.
Warning signs
- A device that is suddenly slow or unresponsive without a clear reason.
- Fans running hard and the device overheating, even when idle.
- Battery draining unusually fast on a phone or laptop.
- High processor usage shown in your task manager or activity monitor.
- Slowdowns tied to a specific website that ease when you close the tab.
Why it often goes unnoticed
Because cryptojacking does not lock your files or steal your identity, it raises no obvious alarm. The symptoms — a hot, slow device — are easy to blame on age or too many tabs. Browser-based cryptojacking can stop the moment you close the page, leaving no trace, while malware-based versions restart with your device and run in the background. The cumulative cost is real: a drained battery, a throttled computer, a higher power bill, and shortened hardware life. Treat unexplained, persistent slowdowns and overheating as a reason to investigate.
Cryptojacking does not announce itself — it just makes your device hot, slow, and tired while someone else collects the coins. Persistent, unexplained sluggishness is worth a second look.
How to protect yourself
Keep your operating system, browser, and security software updated, and install apps and extensions only from official sources. A reputable ad or script blocker can stop many in-browser miners, and closing suspicious tabs ends browser-based mining. Watch your processor usage if a device runs hot for no reason, and remove unfamiliar programs or extensions. As always, protect your accounts with two-factor authentication and a unique password from our password generator, so a compromised device does not also cost you your logins.
Frequently asked questions
What is cryptojacking?
Cryptojacking is the unauthorized use of your device’s computing power to mine cryptocurrency for an attacker. It runs through a malicious app or a compromised website, costing you performance, battery, and electricity while you get none of the coins.
How do I know if my device is cryptojacked?
Look for sudden slowdowns, fans running hard and overheating, fast battery drain, and high processor usage in your task manager. Slowdowns tied to one website that stop when you close the tab point to in-browser cryptojacking.
How do I stop cryptojacking?
Update your system, browser, and security software, install only from official sources, use a reputable script or ad blocker, close suspicious tabs, and remove unfamiliar programs or extensions. Check processor usage if a device runs hot without reason.