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Your phone heating up isn’t always just a quirky inconvenience—sometimes it’s a silent alarm. Behind that rising temperature could be a hidden parasite draining your device’s power, your electricity, and your wallet without ever touching your passwords. This threat is called cryptojacking, a quiet, calculated hijack of your processor that turns your phone or computer into a secret crypto mining machine for criminals. This act adds up to the various crypto scams and attacks launched by malicious entities in the crypto space.
Most victims never realize what’s happening until their devices slow down, overheat, or fail. But the good news? You’re about to learn exactly how this threat works—so you can stop it long before it ever reaches you.
What is Cryptojacking?
Cryptojacking is an unauthorized access to someone else’s computer, phone, or server with a view to stealing crypto assets without the owner’s knowledge or permission. This is the system that is usually employed by attackers so as not to spend money on hardware or electricity, but instead inject mining scripts or malware in victims’ devices surreptitiously to force those systems to do the heavy computations while the attacker profits.
In practice, cryptojacking mostly runs quietly behind the screen, slowing down devices and causing further damage.
Since mining requires high CPU and GPU resources, due to cryptojacking, devices slow down, overheat, and reduce their lifespan-all without the victim’s knowledge. Besides that, devices consume more energy.
The CISA (Cybersecurity & Infrastructure Security Agency) regards cryptojacking as a silent and widespread cyber threat and warns against it. And it can potentially attract degraded system/network performance, increased power consumption, potential hardware damage, and more.
How Does Cryptojacking Work?
1. Browser-Based Cryptojacking (Drive-By Mining)
In browser-based cryptojacking, the attackers inject a website or an online ad with malicious JavaScript mining code. This script automatically begins execution in the browser the very moment a user opens the web page-no installation of the program is required, no permissions or downloads needed.
This technique has been quite well-known during the times of Coinhive, which infected thousands of compromised sites with mining scripts and leveraged visitors’ CPUs. Once active, the script uses up to 100% of available CPU resources, hence slowing down devices while mining Monero-the preferred coin because of its privacy and CPU-friendly algorithm.
These attacks usually spread through compromised websites, infected ad networks, hidden pop-ups, or malicious redirects.
2. Malware-Based Cryptojacking (Installed Miners)
Malware-based cryptojacking works by directly installing a persistent mining program on the device. In most cases, it starts with social engineering in the form of phishing emails, fake installers of any software, cracked apps, infected browser extensions, or malicious cloud workloads.
The malware will drop a miner that will camouflage its presence in system processes and will auto-restart if killed, often disabling antivirus protections as well. Unlike browser-based cryptojacking, this works even after the browser is closed, and can function 24/7.
Modern variants might also spread laterally across networks, infect IoT devices, abuse misconfigured cloud servers, or remotely deploy miners by exploiting vulnerabilities like CVE-2021-44228 (Log4Shell).
Why Do Attackers Prefer Cryptojacking?
1. Low Entry Barrier for Criminals
Since being a successful cryptojacker does not require expert hacking, anyone can have a successful cryptojacking career with minimal effort. So, instead of performing the complicated stuff like breaking into financial systems or executing complex ransomware campaigns, all they need to do is send simple scripts that quietly exploit device resources.
Once the script is in the system, the job’s done. It can run for as long as possible with little maintenance, allowing criminals to make steady crypto income with almost no operational risk.
2. Minimal Risk of Detection
Cryptojacking is sneaky. It doesn’t announce itself. It works by hiding deep inside your device and stealing tiny bits of your computer’s power to secretly mine crypto. Cryptojackers do not overburden one system; they steal pieces from different people so that the victims may not notice until their system starts overheating. In this way, they make so much money off victims without being detected.
3. Scalable With Little Effort
Cryptojacking is such an easy way of making money at scale. They get a tiny piece of code onto thousands of devices at once-through a bad link, a fake extension, or an infected app. Once that code is there, every single device makes money passively for them. What’s more, for the criminal this is all free. They aren’t paying for hardware, they aren’t paying for maintenance, they aren’t paying the electricity bills-you are literally funding their lifestyle.
Signs Your Device May Be Cryptojacked
1. Unusual CPU or GPU Spikes
If your device gets hot, loud, or slow suddenly, even at times when you are running no serious applications, then cryptojacking may be active. This happens because mining processes running in the background have depleted the processing power. In the case of mining, there is constant spiking of the GPU or the use of the CPU above the normal idle levels, meaning that your hardware could be minting coins for an attacker.
2. Overheating or Reduced Battery Life
Because the hidden program is siphoning your device’s power, your gadgets may start to overheat and battery discharge will happen much faster. If your phone feels hot and you’re not even on it, or if your laptop fan is always on intensely and you are only writing an email, that is a sign. Basically, if your system, which normally worked okay, suddenly starts overheating for no reason, then you may be working for someone without knowing it.
3. Browser Tabs Freezing or Lagging
These bugs automatically run a script in the background when you visit any website containing these bugs, without your knowledge. If you are working on something in your browser and it suddenly starts freezing or if pop-ups keep coming up, then that is probably cryptojacking occurring.
4. Slower Overall System Performance
If you have been running your system and have been performing quite a few tasks on it, and all of a sudden, while composing an email, it starts lagging, then something is definitely wrong. It might be because something else is drawing all the power; hence, the moment it starts slowing down your system, draw your attention towards it and get it checked.
What Are the Common Targets of Cryptojacking?
1. Personal Computers and Laptops
It is far easier to attack the people’s personal devices, as all hackers need to do is send a link with these bugs or go through their browsers or downloads. Once they have access, they have total mining power without the user noticing.
2. Smartphones and Tablets
Hackers know that people may not think anything of it if their phones start to overheat or act up; they will just associate this with the brand of the phone. Also, phones are usually connected to the internet, and security is a lot less, so they stand a better chance of success when they hack into a phone or tablet.
3. Cloud Servers and Enterprise Systems
Bad guys target big corporate cloud systems because they’re actually giant free warehouses of computing power, just begging to be exploited. If they discover a single security flaw or a purloined password, they can turn thousands of powerful, compromised computers in an instant into their very own, secret crypto-mining operation.
How to Prevent Cryptojacking
1. Use Good Security Tools
Because of that, dependable security software stands out as one of the strongest defenses against cryptojacking. It can detect mining scripts, remove hidden malware, and block unauthorized background processes. Tools like Malwarebytes, Bitdefender, or Kaspersky are widely validated by cybersecurity analysts for the early detection of cryptomining behavior. These programs keep your system constantly on watch for strange CPU usage, malicious downloads, and suspicious activities done on the browser, not allowing silent crypto-mining infections to affect your system.
2. Install Browser Extensions That Block Mining Scripts
Browser-based cryptojacking happens in the blink of an eye, and extensions like NoCoin and MinerBlock offer essential protection, preventing mining JavaScript from running on websites. These work by parsing site scripts in real time and blocking any known cryptomining signatures before they can affect your CPU. Such tools also defend against malicious ads, pop-ups, and compromised sites, effectively stopping drive-by mining attacks that run without downloading anything to your device.
3. Keep Your Software and Browser Updated
Outdated operating systems, browsers, and plugins often contain vulnerabilities that attackers use to install mining malware or inject scripts remotely. Regular software updating means security patches close these gaps, preventing miners from sneaking into your system. Automatic updates significantly reduce the risk of cryptojacking, since many mining attacks target old versions of browsers and apps lacking modern protections against malicious code execution.
4. Be Careful When Clicking Links
Cryptojacking malware most often spreads through phishing emails, fake downloads, and unsafe links tricking users into installing hidden miners. Always check who sent a link and avoid downloading software from sites you don’t trust or ads that seem fishy. Cybercriminals rely on human mistakes, so cautious browsing habits greatly reduce the chance of accidentally triggering a mining script or downloading malware that runs silently in the background.
5. Use Strong Firewalls for Business Networks
Organizations have a greater chance of being subjected to cryptojacking attacks, since these target large networks with strong hardware. A correctly configured firewall supports the detection of abnormal CPU or network utilization, blocking unauthorized scripts, and miners from calling external servers.
Businesses should go ahead and turn on intrusion detection systems and block scripts from running from unknown domains. These measures will prevent cryptojacking from successfully spreading across servers, employee devices, and cloud environments in corporate networks.
6. Use Website Protection within Your Security Suite
Website protection in today’s security suites includes features to automatically detect cryptomining behavior on webpages, ads, and embedded scripts. These tools monitor for unusual code execution, excessive CPU usage, and known cryptomining domains, which they block before anything exploits your device. By filtering dangerous websites in real time, website protection adds an extra layer of security that stops both browser-based and malware-based cryptojacking attempts.
Things to Do If You Suspect Your Device Being Hacked
1. Run a Deep Scan
You can do this with a good antivirus tool. It will help you uncover and unmask hidden mining scripts. When it finds them, it will be stopped immediately, and everything will go back to normal.
2. Delete Unknown Apps
Pay attention to all your browser add-ons and phone apps so that if you see something you didn’t put there, you can remove it, so that if that is how those hackers are accessing your system through that, they will be let go.
3. Monitor Resource Usage and End Unknown Tasks
If your system suddenly starts getting hot, then something might be wrong. To understand what the problem is, carefully analyze your Task Manager if you use Windows or or Activity Monitor if you use a Mac), and if you find any program that is running and you are not sure of it, clear it up. If it’s still there, call a professional.
4. Keep Your Software Updated
Always make sure that you are using the newest software for your devices. Using old programs is risky because attackers know exactly how to get past their weak, outdated security. By simply keeping everything updated, you apply the latest fixes and protect yourself from being easily attacked.
Frequently Asked Questions (FAQs) About Cryptojacking
Which cryptocurrency do criminals usually mine?
Almost always Monero (XMR). It’s best for stealing power because it’s hard to trace and easy to mine on a regular computer.
Can cryptojacking harm my computer?
Yes. It makes your computer or phone work non-stop, and this causes it to overheat and wear out much faster, so your system will get spoiled faster.
Can my mobile phone get hit by this?
Yes. It’s very common, and people who use Android phones usually fall victim more. You can be attacked if you download a bad app or visit a bad website.
How do I know if my browser is hijacked?
Open your Task Manager (or Activity Monitor) to see your CPU usage. Then, close your browser completely. If the CPU usage instantly drops to zero, then the problem is with the website or extension.
Conclusion
Cryptojacking is a big deal. It is even worse because it could be going on for months, and you might not be able to tell. People who do this are preying on your inability to pay attention to details and your negligence. Do not let them win. Learn to dictate this in time and learn how to shut it down so that you can have a havoc-free trading experience.
Last updated on December 5, 2025
