Despite a crash that saw the price of Bitcoin and other cryptocurrencies plummet, the fever is not dead. Look no further than the race for computing power, which is reaching new and bizarre heights.
Cryptocurrencies in general and Bitcoin in particular requires an enormous amount of computing power to mine. That's by design. As the difficulty of mining goes up, the cyber-prospectors of this new gold rush are employing all kinds of methods to corner as much horsepower as they can: Buying up graphics cards in bulk, co-opting high-tech government equipment, and most recently, illicitly employing the services of thousands of web browsers.
Cryptojacking, as this process is often called, has exploded in popularity ever since folks figured out how to sneak it into websites using Javascript. Some websites, like Salon.com, are even using the tactic on the up-and-up as an alternative form of economic support. Cryptojackers typically have no interest in invading your privacy or messing up your computer, but the power they pull can trash your battery life and put strain on your device. If the prospect of your computer being used for such purposes without your consent makes you a little nervous, there are a few ways you can try to stop it.
How To Spot Cryptojacking
Surreptitious forms of cryptojacking can be cleverly hidden. One website, for example, was hiding a cryptojacking script in a browser tab icon.
Fortunately, even the most well-hidden cryptojacking scripts necessarily reveal themselves in action. To do their work, they need to use a very noticeable amount of CPU power, enough that it might make your laptop's fans kick on or slow down your system's overall performance.
If you notice either of these conditions and get suspicious, just pull up your Task Manager on Windows (Ctrl+Alt+Delete) or Activity Monitor on a Mac (Command + Space and search for "Activity Monitor"). If your web browser is pulling a particularly high percentage of CPU power (close to all of it), there might be a cryptojacker at play.
If you suspect a certain website is to blame, you can test your theory by closing the tab and monitoring the results or, in Google Chrome, go to the Menu, then More Tools, then Task Manager to check CPU usage by tab.
How To Block It
Because modern browsers have a remarkable amount of access to your computer's hardware, and because cryptojackers take advantage of some of the very services that make websites work, it's tough to flip a switch and simply block them all with a snap.
Browser extensions like No Coin for Chrome or Firefox and MinerBlock for Chrome will attempt to block connections that match up with known cryptojackers. This should work in some cases, but it's not a sure thing. These extensions will remain effective only as long as their databases are updated with the newest threats, and innovative cryptojackers could find ways to slip by.
The more severe solution, and one that's likely to be more trouble than it is worth, is to block Javascript altogether, or set up your browser so that scripts can only run with your permission. Extensions like ScriptSafe for Chrome and Firefox will tell your browser to warn you before scripts run, but it will make everyday browsing a serious hassle. Chrome and Firefox also have settings to turn off Javascript entirely, but that will make most of the web unusable. Resort to these options at your own annoyance.
There's no perfect solution, but these measure mixed with a little bit of vigilance can help you defend yourself from the latest scourge of the web until Bitcoin finally bottoms out for good.
