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Summary: What is cryptojacking?
Cryptojacking is a form of cybercrime in which hackers use your PC for cryptomins. They do this because cryptomining can be very lucrative, but is also very taxing on your hardware and power. That is why they prefer to use your hardware and also make you pay for the high electricity costs of cryptomining.
It is therefore very important to recognize, prevent and, if necessary, remedy cryptojacking. You can recognize cryptojacking by, among other things, poorer PC performance, overheating of your device and increased CPU usage.
Detecting, preventing and remedying cryptojacking is difficult, because modern forms of this type of cybercrime often do not even leave a trace on your PC. That is why we recommend that you read our extensive article on cryptojacking below to arm yourself as well as possible against this vicious form of cybercrime.
With the advent of Bitcoins and other cryptocurrencies, a new kind of cybercrime has emerged: cryptojacking. Cryptojacking is the use of someone else’s computer to mine cryptocurrencies. In this article you can read what cryptojacking is exactly, how to detect and prevent it and what you can do if it has happened to you.
To properly understand what cryptojacking is, you actually also need to know what cryptomining (and bitcoin mining) is. This is the purpose of a “cryptojacker”. That is why we first explain below what cryptomining entails. What is Bitcoin mining and cryptomining?
To understand what Bitcoin and cryptomining is, you first need to know roughly how the blockchain works. We will mainly focus on Bitcoin, because this is the most common cryptocurrency. The blockchain is, as it were, the digital cash book in which all cryptocurrency transactions are recorded. If you have a computer or system with crypto software, then you have a copy of this blockchain on your computer. Incidentally, not all cryptocurrencies work on the basis of a blockchain. How does cryptomining work?
A cryptominer verifies a crypto transaction made, for example a Bitcoin transaction. In the case of Bitcoin, the miner can make money by verifying one “block” of Bitcoin transactions. One such block amounts to 1 MB of data. In other words, to qualify for Bitcoins, a miner may need to verify one transaction, but it could just as easily be 1000. This depends purely on the complexity and data of the transaction(s). If such a block is verified by the Bitcoin miner, this block is added to the blockchain.
In other words, in exchange for the verification work that the Bitcoinminer does, Bitcoin rewards it with Bitcoin. The miner can use this as an investment (Bitcoin is becoming more and more valuable globally) or as an online payment method. This is roughly how cryptomining (so not just Bitcoin mining) works. Why Bitcoin mining?
The reason for miners to cryptomin is simple: they want to make cryptocurrency (and therefore money). For Bitcoin, cryptomining also has two advantages: first, cryptominers ensure that people do not abuse the system by spending the same Bitcoin twice, because they control the transactions. In addition, miners also introduce new Bitcoins into the network, causing it to expand. After all, the miners are rewarded with new Bitcoin. The expectation is that this will stop once, approximately around 2140. Around this time, bitcoin is expected to transition to a system where the rewards for verifying transactions by miners are covered by Bitcoin users. What exactly is cryptojacking and why does it happen?
Cryptomins usually require special, very powerful hardware and a lot of power. Many cryptominers are only too eager to mine Bitcoins, without having to pay for the costs of this hardware and power themselves. This is exactly why they take over other people’s computers and systems so that they can do their job. That’s cryptojacking. Just like with a botnet, your computer is put in the service of a hacker.
Maybe you think you can’t become a victim of cryptojacking because you don’t have that powerful “cryptojacking hardware” anyway. Unfortunately, this is not true. Cryptojacking usually does not take place through targeted attacks on specific systems. You can read more about this in a moment. In addition, nowadays there are also cryptocurrencies that you can mine where you do not need a special “dedicated GPU” (a graphics card intended for intensive graphics tasks or cryptominen) or other special hardware. Consider, for example, a cryptocurrency such as Monero, which can be mined on the basis of CPUs (the central processor that every PC has). So never simply assume that you are safe from cryptojacking.
Cryptojacking may not have any direct negative consequences for you, but it does mean that your hardware will fail sooner and your power consumption (and therefore costs) will increase considerably. Later in this article, we’ll explain how to detect and prevent cryptojacking so you can avoid these nasty consequences. But first, we’ll explain how cryptojackers can access your computer. This way you already know better what to look for when preventing cryptojacking. How does a cryptojacker access my computer?
There are two main ways for cryptojackers to access your PC.
- The hacker injects a “cryptojacking script” directly into your computer, as soon as you click on a certain illegitimate link, for example. This is often accompanied by phishing techniques.
- The hacker ensures that the “cryptojacking script” ends up on a frequently visited website, so that computers that visit this website automatically cryptomin.
Note: the second way of cryptojacking, via frequently visited websites, is very difficult to detect, because no cryptomining code ends up on your computer. This script is executed directly from your browser on your computer, instead of from your PC itself. Therefore, virus scanners will often not recognize this form of cryptojacking, also called “browser-based cryptomining”.
The script that gains access to your PC in the above ways ensures that your system cryptomins in the background (so without you noticing). The second way, via frequently visited websites, is the most common. This is very tricky, because it means that you can be cryptojacked without realizing it. Fortunately, there are still ways to prevent this. We will discuss these at the end of this article. What are the consequences of cryptojacking?
The cryptojacking code works unnoticed in the background of your system. The CPU and GPU power, memory and bandwidth of your computer are then used to mine cryptocurrencies. This causes your computer to suddenly become many times slower. Because of this intensive use, your computer will also break down faster. It can also lead to higher electricity costs. In the end, it costs you money, without you having anything left over. In addition, it is of course not a nice idea that you and your system are used for illegal activities. After all, there is nothing wrong with cryptomins themselves, but cryptojacking someone’s PC for this is indeed prohibited. How do I detect cryptojacking?