Cryptojacking: How Hackers are Using Your Devices to Mine Cryptocurrency

18 August 2025

Ever feel like your computer is slugging along even though you just closed all your tabs? Or maybe your phone heats up like a toaster when you’re just scrolling through memes? Don't shrug it off just yet—it might not be a random tech glitch. You could be the unsuspecting victim of something sneaky and sly called cryptojacking.

Sounds like a sci-fi hack into the Matrix, right? Not far off.

Cryptojacking is one of the quieter, creepier corners of cybercrime. It’s stealthy, it’s smart, and unfortunately, it's becoming increasingly common. So, let’s peel back the curtain on this digital crime and understand what it is, how it works, and most importantly—how to keep your devices safe.

What the Heck is Cryptojacking?

Alright, let’s break it down.

"Crypto" stands for cryptocurrency (like Bitcoin, Monero, or Ethereum), and "jacking" as in hijacking. Put them together and you’ve got: hackers sneaking into your devices to mine cryptocurrency without your permission.

Think of it like someone moving into your house without you knowing. They use your electricity, your food, even your couch, and leave you with a high bill and zero benefits. That's pretty much what cryptojackers are doing—only digitally.

They run mining scripts on your device in the background. Your CPU or GPU does all the heavy lifting, and the hackers pocket the digital coins. No hacks on your bank or sensitive data (not directly, anyway), so most people don’t even notice. But your system slows down, your battery drains faster, and your energy bill might hit the ceiling.

Why Do Hackers Love Mining Cryptocurrency?

Good question.

Cryptocurrency mining requires enormous computational power. To create new coins (especially privacy-focused ones like Monero), miners need to solve complex mathematical problems. This takes a lot of electricity and high-end hardware. And that’s expensive.

Wouldn’t it be easier to just "borrow" other people’s devices? Exactly.

That’s where cryptojacking comes in. It’s a slick, low-risk, high-reward way for cybercriminals to earn passive income—on your dime.

How Does Cryptojacking Work?

Cryptojacking is stealth mode hacking. There are two main techniques hackers use:

1. Malware-Based Cryptojacking

This involves tricking you into downloading malicious software—maybe from a shady link in an email or a sketchy website plugin. Once installed, the malware quietly mines crypto in the background every time your device is on.

And here’s the worst part: It doesn’t even need internet access constantly. Once it’s in, it’s in.

2. Browser-Based Cryptojacking (a.k.a. "Drive-by Mining")

Ever visited a site and your fan suddenly gets louder for no reason? You might be a victim already.

Certain websites (legit or compromised) contain scripts that run mining code while the page is open. As long as you're on the site, it's using your CPU power to mine cryptocurrency. Close the tab, and the mining—which could’ve netted some coins for the hacker—stops.

Some sites even intentionally use mining scripts as an alternative to showing ads. That’s controversial, to say the least. We’ll get into that soon.

Signs You Might Be Getting Cryptojacked

So, how do you know if you’re being cryptojacked? It’s tough to catch because there aren't flashing red warnings. But your device will show signs if you know what to look for.

Here are some clues:

- Your device is unusually slow – Basic tasks take longer? That’s a red flag.
- CPU usage is through the roof – Check your Task Manager or Activity Monitor.
- Battery drains super fast – Especially when you’re doing almost nothing.
- Device overheating – Your laptop feels like it’s trying to fry an egg.
- Browser gets laggy – Especially on specific websites.
- Fan noise – That little fan spinning like it’s training for a marathon.

If your computer is working harder than it should without a clear reason, it’s time to investigate.

Why You Should Be Concerned

You might be thinking, "Well, at least they're not stealing my identity, right?"

Sure, but cryptojacking is still bad news.

- Shortens Device Lifespan: Running your CPU at high performance 24/7 wears it out fast.
- Kills Battery Health: Constant power draw damages long-term battery capacity.
- Jacks Up Electricity Bills: Especially if you’re on a desktop or server.
- Compromises Security: If hackers got in to mine crypto, what’s stopping them from doing more?

It’s like a parasite. Even if it’s not lethal, it drains you over time.

Common Cryptojacking Tools and Scripts

Let’s call out some of the usual suspects. The most common cryptojacking tool is Coinhive, which despite being shut down in 2019, laid the foundation for a lot of copycats.

These scripts are usually embedded in websites using JavaScript. Others include:

- Crypto-Loot
- Minr
- CoinImp
- DeepMiner

Hackers often deliver cryptojacking malware using phishing emails, fake browser extensions, and even pirated software. Basically, if it’s too good to be true, it probably is.

The Monero Factor: Why This Coin Is the Favorite

When it comes to cryptojacking, Monero (XMR) is the go-to coin. But why?

- Privacy: Monero transactions are private and difficult to trace.
- Easier to Mine: Doesn’t require specialized hardware like Bitcoin.
- CPU-Friendly: Perfect for mining on regular computers and phones.

Hackers love Monero because it’s like the Swiss bank of crypto—anonymous and efficient. When you're stealing resources, you don’t want a fingerprint left behind.

Real-Life Examples of Cryptojacking in Action

Cryptojacking isn’t just some obscure cybercrime—it’s happened to big names too.

- Tesla: In 2018, hackers sneaked into Tesla’s cloud system and used it to mine crypto!
- Los Angeles Times: Hackers injected a mining script into one of their servers.
- Government Websites: Over 4,000 US and UK government websites were once infected with Coinhive scripts.

If tech giants and government sites can get cryptojacked, no one is immune.

Is Cryptojacking Ever Ethical?

Let’s stir the pot a little.

Some websites and app developers argue that instead of showing ads, they’ll run a mining script while you use their platform. You’re getting content, they’re getting crypto. No pop-ups, no banner ads—just a silent agreement.

But here's the kicker: most don’t ask for your permission. That’s where it crosses the line.

Ethical cryptomining needs transparency and consent. Otherwise, it’s just digital pickpocketing.

How to Protect Yourself from Cryptojacking

Okay, now that you’re officially creeped out, let’s talk about defense. Good news is, you’ve got options.

1. Use a Reliable Antivirus and Keep It Updated

Many antivirus programs now include cryptojacking protection. Make sure it's updated regularly and actively scanning.

2. Install a Cryptojacking Blocker

Browser extensions like:

- No Coin
- MinerBlock
- uBlock Origin

These block known mining scripts from running on websites.

3. Monitor CPU Usage

Keep an eye on your CPU. If it’s spiking when idle or when visiting certain websites, something’s off.

4. Avoid Sketchy Links and Downloads

Don’t click on fishy email attachments or download pirated software. Ever.

5. Keep Your Software Up-to-Date

Old software = vulnerabilities. Always update your browser, OS, and plugins.

6. Disable JavaScript (Selectively)

Drastic, but effective. Some cryptojacking scripts run entirely on JavaScript. Disabling it can help—but it might break a lot of websites.

What to Do If You Suspect Cryptojacking

If your spider senses are tingling, here’s your action plan:

1. Disconnect from the Internet – Stop the mining process.
2. Run a Full Malware Scan – Use a credible antivirus or malware removal tool.
3. Check Browser Extensions – Remove any suspicious ones.
4. Reinstall Browser or OS – If the infection is deep, a clean install might be necessary.
5. Change All Passwords – Just in case they snuck off with more than just your CPU juice.

Final Thoughts: Stay Alert, Stay Smart

Cryptojacking isn't flashy. It won’t display a ransom note on your screen or steal your grandma's cookie recipes. It’s silent, sneaky, and selfish—and that’s what makes it so dangerous.

We're living in a digital world where even your fridge might get hacked someday. (Yep, smart appliances are at risk too.) So, being aware of cyber threats like cryptojacking isn’t just optional—it’s essential.

Keep your software updated, don't trust everything you click, and protect your CPU like it's your digital heart—because in a way, it is.

Stay curious, stay skeptical—and don’t let anyone mine crypto off your back.