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What Is Cryptojacking?

What Is Cryptojacking?

 By Charles Joseph | Cybersecurity Researcher
 Published on August 2nd, 2023
This post was updated on November 25th, 2023

Cryptojacking refers to the unauthorized use of a person’s computer or other connected devices to mine cryptocurrencies. Typically, hackers would do this by either tricking a user into clicking a malicious link in an email or an ad, which loads crypto mining code on the computer or by infecting a website or an ad with JavaScript code that auto-executes once loaded in the victim’s browser. The victim’s device then secretly mines cryptocurrency on the hacker’s behalf.

Cryptojacking Examples

1. Email-Infection Example

In this instance, you might receive an email that appears completely normal. It could even make you believe it came from someone you know or a reputable source. The email might contain a compelling call to action – perhaps an urgency to confirm account details, view an invoice, or check out an intriguing piece of news hosted on an external website.

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Once you click this malicious link or download an attachment from the email, that’s when the hacker strikes. Unbeknownst to you, the crypto-mining scripts start to run in the background of your device. These scripts hijack your device’s resources – specifically, its computing power – to mine cryptocurrency for the hacker.

Throughout this process, there’s no obvious sign that anything is amiss. Your computer doesn’t behave differently, and there are no obvious signs of an infection. The only giveaway might be a slower performance due to the mining process utilizing your device’s processing power. This example demonstrates the stealthy and deceptive nature of cryptojacking, making it a widespread issue in the digital world.

2. Website Infection Example

Imagine you are browsing your favorite news site. This is a website you trust and visit often. However, suddenly, your computer starts to lag. Pages are slow to load, videos buffer, and even your mouse moves sluggishly. This might be a moment when cryptojacking is happening.

How did it occur? A hacker may have injected a cryptojacking script into the code of the website. The script can be embedded in multiple parts of the website—maybe in an ad, a picture, or even a text section. As soon as you load the website, the script starts running automatically. The JavaScript code now leverages your device’s processing power to mine cryptocurrency for hackers while you browse.

Throughout this, you don’t receive any notifications, nor does your antivirus software alert you. In the most deceptive ways, with only a simple visit to a trusted website, your device’s resources are being used for the benefit of the hacker. This example really underlines how cryptojacking can sneak up on users without any obvious signs.

3. Network Server Infection Example

In this case, let’s consider a business company with a large network of computers. It’s a regular workday, and employees are using their computers as usual. However, some might start noticing their systems are slower than usual. What’s causing this? Cryptojacking could be the culprit here.

A hacker may have gained unauthorized access to the company’s network servers. Instead of targeting just one computer, they infect the entire network with a crypto-mining script. This method can be more lucrative because they can use the combined power of multiple devices for mining cryptocurrency.

In such a situation, the signs of cryptojacking might not be as immediately noticeable. The performance degradation might seem minimal at first at the individual machine level, but over a network of computers, the impact is significant. As a result, business productivity might suffer, illustrating the expansive and harmful potential of cryptojacking on a larger scale.


Cryptojacking, though relatively silent, can significantly impact individuals and businesses by secretly exploiting their computing resources for cryptocurrency mining. By understanding the examples provided and taking necessary precautions, users can guard themselves against this intrusive online threat.

Key Takeaways

  • Cryptojacking is the illicit use of a person’s computer or connected devices for mining cryptocurrencies without their knowledge.
  • Methods of cryptojacking include infecting the user’s device with malicious links or scripts or compromising website codes to mine cryptocurrencies once loaded on the user’s browser.
  • One prime indication of cryptojacking is a noticeable decrease in device performance or battery life due to the strain on the device’s resources.
  • Entire network servers can also be targeted by cryptojacking, causing a significant decrease in overall system performance and potentially impacting business productivity.
  • While not immediately visible, increased awareness and early detection tools can help users guard against cryptojacking attempts.

Related Questions

1. How can I protect my device from cryptojacking?

Stay safe online by not clicking on suspicious links or attachments and keeping your software up-to-date. Use a reliable security software that can detect and block cryptojacking scripts. Also, consider installing a browser extension that prevents scripts from running without your permission.

2. How does cryptojacking affect my device?

Cryptojacking strains your device resources by utilizing its processing power to mine cryptocurrencies. This could cause your device to slow down or operate poorly, and in the case of mobile devices, it may deplete the battery faster.

3. Is cryptojacking illegal?

Yes, cryptojacking is considered illegal as it involves unauthorized access to personal devices and uses their resources without obtaining the owner’s consent.

4. What happens after a cryptojacking attack?

After a successful cryptojacking attack, the hacker begins to mine cryptocurrency using the resources of the infected device. The mined cryptocurrency is then transferred to the hacker’s wallet without the victim’s knowledge.

5. Can I detect if I’m a victim of cryptojacking?

While cryptojacking often does not show obvious signs, a sudden slowdown in device performance can be an indication. Tools are now available which can check if your device is running a crypto-mining script.

"Amateurs hack systems, professionals hack people."
-- Bruce Schneier, a renown computer security professional
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