What Is Cryptojacking? Explained Simply

What cryptojacking is

Cryptojacking is a type of attack where someone secretly uses your device's computing power to mine cryptocurrency for their own profit, without your knowledge or consent. Mining cryptocurrency requires significant computing resources and electricity, so instead of paying for their own, attackers hijack other people's devices to do the work. Your device does the mining, bearing the cost in performance and electricity, while the attacker collects the rewards. It is theft of your computing resources, often running quietly in the background.

Why attackers do it

Mining certain cryptocurrencies is profitable but expensive, requiring lots of processing power and electricity. Cryptojacking lets attackers get that computing power for free by stealing it from unsuspecting victims. By spreading their mining across many hijacked devices, they can generate cryptocurrency while someone else pays the electricity bills and suffers the slowdowns. Because it can run quietly and does not necessarily steal data, cryptojacking can continue undetected for a long time, steadily profiting the attacker.

How cryptojacking works

There are two main approaches. One uses malware: the attacker infects your device with mining software that runs hidden in the background, using your resources continuously. The other happens through the browser: a malicious or compromised website runs mining code while you are visiting, using your device's power as long as the page is open. In both cases, your device's processor is put to work mining cryptocurrency for the attacker, draining performance and power.

The signs

Cryptojacking often reveals itself through performance symptoms, since it heavily uses your device's processor. Warning signs include your device becoming noticeably slow or unresponsive, running hot, fans spinning loudly, and the battery draining quickly on laptops and phones. You might also notice high processor usage even when you are not doing anything demanding. These symptoms, especially a device working hard for no apparent reason, can indicate that something is secretly using your resources to mine.

How to protect your devices

Protecting against cryptojacking combines general malware defense with some browser care. Keep your system and software updated, use reputable security software that can detect mining malware, and be cautious with downloads and links. For browser-based cryptojacking, keeping your browser updated and using extensions that block mining scripts can help, as can closing suspicious sites. Watching for the performance warning signs lets you catch cryptojacking that slips through, so you can investigate and clean your device.

Why it matters

Cryptojacking is a sneaky form of attack that steals your device's computing power and electricity to enrich attackers, often without stealing data or announcing itself. Understanding it clarifies why a device might suddenly run slow and hot, how attackers profit from your resources, and how to protect yourself. As cryptocurrency remains valuable, cryptojacking stays relevant, making it a useful threat to understand and guard against.

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See also: Types of malware explained: viruses, trojans, spyware, What is a botnet? Explained simply.

Sources

• Cryptojacking - Wikipedia

Published date reflects the original event date (2023-10-03). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.