Cryptocurrency miners are a new scourge on the web. Web pages can now embed JavaScript code that runs in your web browser to mine themselves Bitcoin or other cryptocurrencies using your computer. The website keeps the cryptocurrency, and you get higher electric bills, 100% CPU usage that drags down your computer, and reduced battery life.

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This problem first came to popular attention with the CoinHive script, which ran when you visited The Pirate Bay, but there are other mining scripts and other websites using them. In fact, researchers even discovered a method that allows a site to mine cryptocurrency after you’ve closed the browser tab. So what can you do? Thankfully, there is some software that can help.

Why Doesn’t My Browser Block Them?

Web browser developers are debating ways to stop cryptocurrency miners. For example, Google Chrome’s developers are discussing how to solve the problem in this bug tracker thread.

Chrome’s developers don’t want to just keep a blacklist of cryptocurrency miners, so they’re considering adding a permission that prevents web pages from constantly using all your CPU resources without your permission.

Some adblockers also block cryptocurrency miners, but we don’t recommend using those because the web runs on ads. Blocking all ads will only encourage more websites to use cryptocurrency miners and other terrible things against users without adblock.

Hopefully, browser developers will decide on a solution that helps protect everyone from cryptocurrency miners in the future.

Option One: Use Antimalware Software That Blocks Miners

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While web browsers themselves aren’t blocking cryptocurrency miners yet, some antimalware and antivirus programs already are. For example, the Premium version of Malwarebytes, an antimalware tool we highly recommend, now automatically blocks cryptocurrency miners on web pages you visit.

The integrated Windows Defender antivirus software doesn’t block CoinHive or other cryptocurrency miners on web pages. If you use another antivirus program, it may or may not be blocking cryptocurrency mining scripts like CoinHive—check with your antivirus provider to see if they do.

Option Two: Install the “No Coin” Browser Extension

Alternatively, there are now browser extensions that automatically block cryptocurrency miners for you, and they’re regularly updated with new mining scripts that spring up.

We don’t like recommending browser extensions because we’ve seen good extensions go bad and turn into adware too many times, but there’s really no avoiding it in this case—if you refuse to run antivirus or antimalware software that blocks currency miners, you’ll need a browser extension of some sort.

We recommend the No Coin extension, available for Google Chrome, Mozilla Firefox, and Opera. It’s open source, is the most popular extension of its type, and does a great job of blocking Coin Hive and other similar cryptocurrency miners. You can even whitelist a certain miner and allow it to run, if you like.

The No Coin extension is not available for Microsoft Edge, Apple Safari, or Internet Explorer. If you use one of these browsers, you’ll need another solution—like an antimalware program that blocks cryptocurrency miners.

There are also other ways to block these scripts, such as editing your hosts file to redirect them and prevent web pages from loading the scripts. However, you’d have to keep the list of blocked miners up to date on your own, so it’s better to use an automatically updating piece of software that can maintain that list for you, like a browser extension or security program.

RELATED: What Is an Anti Mining VPN?

Using a cryptocurrency miner to give revenue to a website could be an interesting tradeoff—at least, it could be if websites that used miners informed you that a miner was running and allowed you to make an informed decision. But you probably won’t notice unless you see a web page is maxing out your CPU, and that’s the problem here. Most web pages that use miners don’t provide any indication they’re using your CPU.

Image Credit: BTC Keychain on Flickr (modified)

Profile Photo for Chris Hoffman Chris Hoffman
Chris Hoffman is Editor-in-Chief of How-To Geek. He's written about technology for over a decade and was a PCWorld columnist for two years. Chris has written for The New York Times and Reader's Digest, been interviewed as a technology expert on TV stations like Miami's NBC 6, and had his work covered by news outlets like the BBC. Since 2011, Chris has written over 2,000 articles that have been read more than one billion times---and that's just here at How-To Geek.
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