Table of contents
- What is cryptojacking?
- How does cryptojacking work?
- How to recognize a cryptojacking attack
- Why is it so widespread?
- How to protect yourself from cryptojacking
- How dangerous is it?
Cryptojacking is a growing threat in the world of cyber security. It is a type of malware that uses the computing power of a device, without the user’s consent, to generate cryptocurrency. This often-invisible attack can slow down the system, increase energy consumption, and compromise the lifespan of devices.
This article explains what cryptojacking is, how it works, and how to protect yourself from this insidious threat.
What is cryptojacking?
Cryptojacking is a type of malware that allows cybercriminals to exploit the resources of unsuspecting users’ computers to mine cryptocurrencies like Bitcoin, Ethereum, or Monero.
Unlike other cyber threats, cryptojacking can remain hidden for a long time because it does not directly damage files or systems. Its main goal is to use the CPU to illicitly generate profits.
In practice, a cryptojacking attack can infect any device: from desktop computers to mobile devices like smartphones and tablets. This often happens through JavaScript code loaded onto a compromised web page or malicious applications.
How does cryptojacking work?
Cryptojacking exploits the computing power of victims’ devices to generate cryptocurrency without their knowledge. There are two primary methods used: local malware and drive-by cryptojacking, but both share the same goal: to use the victim’s computer resources to mine cryptocurrency. Here’s how these techniques work:
Local malware: direct attack
The most traditional and invasive method is to infect a device with malicious cryptomining code. This can occur in several ways:
- Phishing emails
Fraudulent emails are a primary vehicle for distributing cryptojacking code. A user receives an apparently harmless email with a malicious attachment or link. By clicking, the code is downloaded and installed, starting to mine cryptocurrency in the background.
- Counterfeit software
Cryptojacking attacks can also occur when users download seemingly legitimate software that contains hidden malware. This often happens with pirated software, free apps from unofficial sources, or fake browser plugins.
- Drive-by downloads
Infection can also occur without any user action. Simply visiting a compromised website can automatically download the malicious code onto the device. Once installed, the malware exploits CPU usage for constant, silent cryptomining.
Once infected, the cryptomining code runs in the background, constantly using the computer’s resources to generate cryptocurrency. As these activities are designed to stay hidden, the user may not immediately notice the infection.
However, there are recognizable symptoms, such as system slowdowns, overheating, and unusual energy consumption.
Drive-by cryptojacking: browser-based infection
Another common method is drive-by cryptojacking, which does not require downloading malware onto the device. Instead, malicious code is embedded in a web page and uses the user’s web browser to mine cryptocurrency.
How it works?
- Hidden JavaScript code
The cybercriminal embeds cryptomining JavaScript code within a website or advertisement. When the user visits the web page, the code automatically executes in the browser and begins to exploit the device’s CPU.
- Silent persistence
While drive-by cryptojacking may stop when the user closes the browser, some advanced techniques can make the code persist.
Example
A hidden pop-under window can remain open even after closing all visible tabs, continuing to mine cryptocurrency.
- Mobile device networks
Even mobile devices, such as smartphones and tablets, can be affected by browser-based cryptojacking. Such attacks can cause overheating, battery damage, and drastically reduced performance.
A notable example of drive-by cryptojacking was Coinhive, a JavaScript script that allowed Monero mining directly in the browser. Although Coinhive was initially designed as a legitimate tool to monetize online content, it was quickly exploited by cybercriminals for unauthorized cryptojacking attacks.
Differences between local malware and drive-by cryptojacking
While both methods share the same goal, they have key differences:
- Local malware:
- Requires installation on the device;
- Works offline;
- Difficult to detect and remove.
- Drive-by cryptojacking:
- Requires no installation;
- Depends on web browser activity;
- Stops when the web page is closed unless code persistence is employed.
Both methods exploit computer resources to perform the complex calculations needed to mine cryptocurrency. In large-scale attacks affecting multiple devices simultaneously, the gains for cybercriminals can be significant.
Why is cryptojacking so effective?
The success of cryptojacking stems from its unique characteristics:
- Difficulty in detection
Since it does not directly damage files or data, cryptojacking can go unnoticed for extended periods.
- Low costs for hackers
Unlike traditional cryptocurrency mining, cryptojacking does not require investments in expensive hardware. Hackers simply exploit victims’ computing power.
- Continuous profits
As long as the malicious code is active, hackers can continuously and automatically generate cryptocurrency.
- Widespread reach
JavaScript code can be easily distributed through compromised web pages or advertisements, enabling cryptojacking to reach many users quickly.
Additionally, with the increasing value of cryptocurrencies like Monero, Bitcoin, and Ethereum, cryptojacking has become an extremely profitable method for cybercriminals.
How to recognize a cryptojacking attack
Although cryptojacking can remain hidden, there are some signs to identify it:
- Device slowdowns
Intensive CPU usage leads to reduced performance.
- Overheating and fan noise
Increased workload causes excessive use of cooling systems.
- Unusual energy consumption
Mobile devices with rapidly depleting batteries may be victims of cryptojacking.
Why is it so widespread?
Cryptojacking has become popular because it is a silent, low-risk method of obtaining cryptocurrency. Unlike other types of attacks, such as ransomware, which require direct interaction with the victim, cryptojacking does not need to demand a ransom.
Simply install the malicious code and start exploiting computer resources to extract cryptocurrency.
Moreover, with the rising value of cryptocurrencies and the increasing difficulty of extracting them through traditional methods, cryptojacking has become a “cheap” solution for cyber criminals.
How to protect yourself from cryptojacking
Protecting yourself from cryptojacking requires a combination of best practices and cyber security tools. Here are some tips to avoid this type of attack:
- Install updated security software
Antivirus and antimalware solutions can detect and block malicious cryptomining code.
- Block JavaScript
Tools like “No Coin” or “MinerBlock” can prevent script execution in web browsers.
- Monitor CPU usage
Check device performance to identify any anomalies.
- Regularly update the operating system and browser and helps protect against exploitable vulnerabilities.
- Avoid suspicious websites and software from unofficial sources.
How dangerous is it?
Although cryptojacking does not destroy files like other types of malware, its impact can be significant:
- Reduced performance
The device becomes slow and less efficient. - High energy consumption
Excessive CPU usage increases electricity bills. - Damage to mobile devices
In severe cases, prolonged workload can damage the battery or processor.
For businesses, the impact can be even greater, with energy-related costs and productivity losses.
Conclusion
Cryptojacking represents one of the most insidious threats in modern cyber security. Its ability to remain hidden while exploiting computer resources makes it difficult to detect and stop.
However, with proper precautions and security tools, both users and organizations can protect themselves from this type of attack and keep their devices secure.
Questions and answers
- What is cryptojacking?
It is an attack that uses a user’s device resources without their consent to mine cryptocurrency. - How does cryptojacking work?
It can occur through malware installed locally or via JavaScript code executed in a web browser. - Which devices can be affected by cryptojacking?
Computers, mobile devices, tablets, and servers can all fall victim to a cryptojacking attack. - How can I detect cryptojacking?
Common signs include device slowdown, overheating, and abnormal CPU usage. - Does cryptojacking damage my device?
Yes, it can reduce performance, increase energy consumption, and damage the battery in mobile devices. - How can I protect myself from cryptojacking?
Use security software, regularly update your system, and block JavaScript in browsers. - What is drive-by cryptomining?
It is a cryptojacking technique where mining code runs in a web browser while visiting a webpage. - Why do cybercriminals use cryptojacking?
Because it is a low-risk and highly profitable method to generate cryptocurrency without direct costs. - Can I stop cryptojacking on my device?
Yes, by installing updated protection software and monitoring CPU usage. - What is the difference between cryptojacking and legitimate mining?
Legitimate mining occurs with the user’s consent, while cryptojacking exploits resources without the victim’s knowledge.
