You know the sound by now. You see an interesting article, you click to open it in a new tab. And then the whirring begins.
For some reason keeping fifteen tabs open was fine with your computer. But that 16th? Now everything is sluggish and your battery is in the red. And if you’re a laptop user, you might even notice your legs heating up while you read that article on the couch.
The whirring noise is cause by your computer’s fan trying to cool down an overworked CPU. For most of us, this is a reminder that it might be time to get a new computer. But few of us suspect that our computers have been hijacked.
Cryptojacking, or the unauthorized borrowing of your computer’s brainpower to make money for someone else, is overworking more and more CPUs. But unlike a virus that sneaks into your computer from opening a malicious file attachment, cryptojacking can happen just from leaving a tab open or watching a YouTube video.
It works like this: the blog, news site, or Wifi connection you trust has no idea that their advertising system is infected with cryptojacking software. You might notice that when you load a page of text, your browser works overtime to keep that page open. You might think the short video ad in the sidebar is to blame, but it’s really the fault of the code behind that video and neither you nor the website owner knows this is going on.
Cryptojacking can be very hard to detect because it is so insidious. If you drove by someone on the side of the road and their car was stopped from a dead battery, you might not mind giving them a jump from your car which was running and recharging its own battery anyway. But cryptojacking is the equivalent of someone draining your battery while you’re parked overnight and siphoning your gas while they’re at it.
Cryptocurrencies like bitcoin and Ethereum require a lot of computing power to keep their systems online. Users who donate their computing power to handle transactions and keep the network up are rewarded with cryptocurrency. The process is called “mining” because of the way it mimics the work required to extract precious resources. But the reward for lending your computing power is so small that in most countries it’s not worth the cost of electricity.
Cryptojacking doesn’t cost cryptojackers a thing, but it will drain your battery and drive up your electric bill. It doesn’t require a download, it starts instantly, and it works without you knowing.
Desktop computer users who are in the habit of leaving their computer running overnight might not even notice that their machines are the electrical equivalent of a leaky pipe. It may seem harmless, but an internal study at Google found cryptojackers can suck up over 75 percent of your CPU load.
In December 2017, Starbucks had to apologize to customers after the WIFI router of their Buenos Aires coffee shop put a 10 second delay on users while it used their computers to mine crypto without telling them. Later that month 100,000 users of Archive Poster—a Chrome extension for Tumblr—were found to be infected.
As soon as we were alerted of the situation in this specific store last week, we took swift action to ensure our internet provider resolved the issue and made the changes needed in order to ensure our customers could use Wi-Fi in our store safely.
— Starbucks Coffee (@Starbucks) December 11, 2017
We all know the basic bargain of the internet: free news and videos in exchange for ignoring some ads here and there. But we are supposed to be in control of these things when we open and close a browser tab. In some cases, the ads themselves might be eating up your computing power. In January 2018 web developer Diego Betto discovered that an infected YouTube ad in his Chrome browser tried to load the mining program Coinhive so he reported it to Google.
What to do about it
If you’re reading this article on a browser running Chrome, look up and to the right of the address bar. Do you recognize all of those icons and how they got there? Most of us have a few extensions to make our email load better. But how do we know if they’re doing what they say they will?
On April 2, 2018, Google tried to weed out these power-draining extensions from their Chromium platform which runs Chrome by banning mining extensions altogether. But that won’t take effect until June. The company has known about the problem for long enough that Chrome users can check out the extensions Minerblock and No Coin.
Not all of your Chrome extensions will appear all the time, though. If you want to check which ones you have running, click on the drop down menu on the top right, then select “More Tools” and then “Extensions.”
You can also see what your processor is up to using the native Activity Monitor program in your Mac or Task Manager on Windows.
If you’re unsure what else might be lurking in your hard drive, download the free Malware Bytes and give your system a checkup every few months. Be advised: it’s free to check your system but cleaning it up might cost you a few bucks. In that sense they are sort of like the dishonest mechanic your mother warned you about. Then again, ignoring the problem is already costing you money, so it’s worth finding an honest mechanic to check it out.