Soaring energy bill, slow network. Are you a victim of cryptojacking?

Thieves stealing petrol out of your tank. Or a neighbour using your electricity connection. That, roughly, is how criminals steal from you using cryptomining malware. They misuse your website without you being aware, in order to collect bitcoin or other cryptocurrencies. It is called cryptojacking.

These thieves do not care about your money or data. They want your devices’ computing power. While you pay a higher electricity bill and your company network runs slower, they make crypto coins. Protect your company from cryptomining malware. For one, by keeping all your devices updated.  

Crypto currency

Crypto coins are digital money. There are several types. Bitcoin (BTC) is the most wellknown. You can use the money to pay via internet. Do you use crypto currency? Then follow the rules for crypto money.  

What is cryptojacking?

Cryptojacking is an illegal form of cryptomining, collecting crypto coins.  


You can buy digital coins. Think of Bitcoin, Ethereum, or Monero. 'Digging up' digital coins is also possible. It is known as cryptomining, and it is legal. You need powerful computers for this, because it takes a lot of computing power. Computing power or processing capacity is the number of mathematical calculations a computer can perform per second. In other words, you earn crypto currency by exchanging computing power.  

They steal a little computing power from thousands of computers at once. Possibly, from your computer as well.


The days when you could use a regular computer to dig up digital coins are far behind us. The required computing power is simply too large, and it is still growing. Cryptominers use valuable equipment and powerful computer networks, that use up a lot of energy. Collecting crypto coins is very expensive.  

Stealing computing power

Cyber criminals do not want to pay for expensive equipment or high energy bills. And so they steal a little computing power from thousands of computers at once. Possibly, from your computer as well. All the stolen computing power together is enough to collect cryptocurrency. This is called cryptojacking, and it is illegal. Cryptojackers earn crypto coins without paying a cent.  

Cryptomining malware

Cyber thieves steal computing power with cryptomining malware. This malicious software runs unnoticed on victims' computers. You get infected by visiting a dangerous website or clicking on a wrong link. Just like other malware, in other words. Criminals place cryptomining malware on all devices with computing power. So also on your smartphone, tablet or server. Is the malware on your device? Then it is unknowingly part of an illegal cryptomining network. 


The malware steals a little bit of your computing power. Think 5 to 10 per cent of the available capacity. As a result, you do not readily notice that your device is infected. The cryptojacker likes to remain invisible for as long as possible. And therefore usually does not steal money or data from you. Nor does it ask you for a ransom, as in a cyber attack with ransomware


Through cryptojacking, some devices in your business unwittingly become part of an illegal computer network, or botnet. Criminals use that botnet for cryptojacking, but possibly also for other illegal things. Think of DDoS attacks on other businesses or further spreading malware. Thus, you unwittingly assist criminals in their crimes. 


A successful infection with cryptomining malware is also a signal to other cybercriminals. It shows that your business network is vulnerable to cyber attacks


How do you notice cryptomining malware running on your computer? A key indicator is that your systems are running slower, or even crashing. Your power consumption is also higher than normal. This is due to the constantly running cryptomining malware. 

Remove it

Think you are infected? Then run a thorough virus scan on all your devices. Your virus scanner may be able to remove the malware. Does that not work? Then you need to restore a backup or even reinstall all software on an infected device. 

Prevent cryptojacking

These tips will help you reduce the chances of a criminal installing cryptomining malware on your device: 

  • Be careful what links you click on and what websites you visit. Infections with cryptomining malware often happen through websites and online advertisements. 
  • Always install updates for your ICT systems right away, especially security updates. And especially when it comes to your web browser. Software that has not been updated may contain vulnerabilities that allow malware to invade your system. 
  • Use antivirus software that specifically protects against cryptojacking. Search the internet for ‘antivirus cryptojacking’. Antivirus software with this feature prevents cryptomining malware from installing itself. And cleans up a possible infection. 
  • Install a ‘coin miner blocker’ plug-in in your web browser. And a general ‘ad blocker’ that stops online ads, including infected ads. 
  • Monitor your ICT systems. Is your computer using more computing power than usual? Perhaps an illegal cryptominer is running in the background. Discovering and solving this pretty quickly is very technical. If necessary, ask your IT administrator (in Dutch) or a cybersecurity specialist for help.