Cryptojacking: What is it, and how does it affect your Mac?

Dawna Roberts

Feb 14, 20245 min read

Cryptojacking: What is it and how does it affect your Mac? Header image

In the world of cybercrime, the objective is usually financial gain. Cryptojacking is just one example of the many types of cyberattacks in which the perpetrator steals money while keeping the victim completely in the dark. But this is one category of threat where the victim may not be personally affected in a major way. Rather, they are used as pawns in a larger game of theft.

What is cryptojacking? The meaning explained

Cryptojacking is a crime where a hacker installs cryptojacking malware onto your device to use it to mine for cryptocurrency. It can be accomplished using computers, servers, tablets, and even mobile phones. Once installed, the malware can affect your device’s performance. It hijacks resources such as bandwidth, memory, and drive space.

How cryptojacking works

Transactions between individuals involving cryptocurrency, digital money often referred to as “coins” or “tokens,” are facilitated using a database technology called blockchain. The blockchain is a record of transactions, but no names or identifying data are used, so it is considered anonymous.

The blockchain requires an enormous amount of energy to sustain it. Accordingly, it relies on people to supply the necessary computing power; they are referred to as “miners.” Someone who allows companies to use their devices for mining receives cryptocurrency as payment.

Criminals who want to receive the rewards of mining without supplying any of the resources (computers, electrical power, etc.) will hijack hundreds or even thousands of devices to use for the blockchain, mining millions in cryptocurrency for their efforts. 

An image of cash and cryptocurrency.
Image by Pexels

Examples of cryptojacking attacks

Some examples of real-life cryptojacking include the following.


In 2017, Coinhive was launched as a cryptocurrency mining service that allowed website owners to make money without ads. They installed a bit of JavaScript on their website that used visitors’ computers to mine cryptocurrency without their consent or knowledge. It was shut down in March 2019 due to new regulations and lack of interest.


FacexWorm is another notable cryptojacking scheme. It uses Facebook Messenger to trick users into clicking on fake YouTube links. The user then downloads a Chrome extension, which is actually malware that hijacks their Facebook account and spreads FacexWorm among the user’s Facebook friends. It also begins to mine cryptocurrency. Plus, the worm steals credentials for specific sites like Google or MyMonero, demanding cryptocurrency payments.

WannaMine v4.0

Another cryptojacking example is WannaMine, a piece of malware first seen in 2018. It spread through a phishing email with a malicious attachment. If a user clicked on the attachment, it installed the malware onto their device and began mining for Monero cryptocurrency. Another feature of the attack vehicle is that it was designed to copy itself to other network devices to boost the mining operation’s computing power. Discovered by security experts in 2020, this threat is adept at avoiding detection and can steal sensitive information from the victim’s device.

Understanding cryptojacking

The trick to protecting yourself from cryptojacking is to understand it fully. Below, you’ll find answers to some of the most common questions asked about cryptojacking.  

How common is cryptojacking?

According to the 2023 SonicWall Cyber Threat Report, cryptojacking is increasing by 43% each year. In 2022, it reached an all-time high of 129.3 million attacks. 

Who is affected by cryptojacking?

Individuals and companies alike may be affected by cryptojacking. In all cases, victims will suffer from decreased device performance, increased power usage, and sometimes stolen credentials or personal information.

Is cryptojacking illegal?

Yes. Even in cases where victims of cryptojacking are not personally harmed in any considerable way, the unauthorized use of their devices and resources is illegal. 

Why is cryptojacking increasing?

Cybercrime gangs are always looking for new ways to make more money with less effort and reduced risk. Security experts theorize that cryptojacking is increasing due to the low level of risk associated with it.

Signs that your Mac is being used for cryptojacking

Cryptojacking is not an obvious crime, so it may be more challenging to detect. Some signs that your Mac is being used to mine cryptocurrency include the following.

Decreased performance

The most significant sign that your Mac is being used for cryptojacking is decreased performance. Watch for a slow response when you click an icon to open a program or file. If you use a laptop, you may see the battery drain quickly. 


Cryptojacking is a resource hog that could cause your device to overheat or shut down. Regular overheating can cause damage to the internal electrical components. If you hear the fan running incessantly, it could be a sign. 

Increased electricity usage

If you notice a steep increase in your electricity bill, it could be a sign that your devices are running 24/7 to mine cryptocurrency. 

CPU usage uptick

Cryptojacking uses a lot of computing power, and if you view your CPU usage logs, you may see a considerable spike. You can check CPU usage by opening the Activity Monitor on your Mac and looking for anything that uses high amounts of resources.

An image showing Mac CPU usage in the Activity Monitor.
Mac and macOS are trademarks of Apple Inc.

How to protect your Mac from cryptojacking

Cryptojacking usually occurs in one of two ways: through a phishing email with malicious links or through a visit to a corrupted website that installs malware automatically. While no one is 100% immune to online threats, there are some ways to help keep you and your Mac safe. 

1. Watch for phishing emails

Never click links in unsolicited emails. You never know where they might take you, and there’s a chance that the link is a tool to install malware on your machine.

2. Use good antivirus/antimalware software

Install and use reputable antivirus/antimalware software on your machine. Run deep scans often to search for anything that could be lurking under the surface.

3. Use browser extensions to block cryptojacking

You can install and use browser extensions like minerBlock, No Coin, and AntiMiner to prevent anyone from using your Mac to mine for cryptocurrency.

A screenshot showing the minerBlock extension.

4. Disable JavaScript and ads

Disable JavaScript on your browser to prevent drive-by installations of cryptojacking malware. Turn on ad blockers to prevent criminals from infecting your device through corrupted ads. 

Protecting yourself from threats should be your number one priority when it comes to cybersecurity. Although the consequences of cryptojacking are more irritating than damaging, it does open the door for additional attacks and can compromise your personal information. 

This is an independent publication, and it has not been authorized, sponsored, or otherwise approved by Apple Inc. Mac and macOS are trademarks of Apple Inc.

Dawna Roberts Dawna Roberts
Dawna has spent her entire career in web dev, cybersecurity, and IT. Her work has been featured on Forbes, Adobe, Airtable, Backblaze, Cyberleaf, Lifewire, and other online publications for the past ten years.