Did you know that some websites are using your computer to mine cryptocurrency? We analyzed our entire index of 175M+ domains to find out exactly how many.
I’ll be honest, up until a few weeks ago, I didn’t know there was such thing as a “crypto mining script” that can be installed on your website.
So let me briefly explain how crypto-mining scripts work. (I’ll try to keep it simple.)
For cryptocurrencies to function, complex computational calculations have to be continually carried out; this process is called mining. Mining is carried out by miners, who earn cryptocurrency by doing so.
It takes a lot of computational power to mine cryptocurrency, which means a lot of energy.
Because energy costs money, some websites install scripts that effectively utilise your computer’s energy to mine cryptocurrency on their behalf. So, the longer you have their site opened in your browser, the more coins they earn using your computer’s energy. (Clever, right?)
SIDENOTE. It’s not always the website owners telemarketing list who install these scripts; many are simply hacked.
Since cryptomining is such a hot trend right now, we thought it would be interesting to find out not only how many sites in the world have crypto-mining scripts installed, but also how many have enough traffic to make this a worthwhile endeavor.
Let’s get to the results!
We crawled all 175,251,729 websites in our database to see how many were mining cryptocurrency.
To clarify, this means that we crawled subdomains, too.
To check for the presence of crypto-mining scripts, we used Wappalyzer.
For those unfamiliar with Wappalyzer, here’s what it does:
Wappalyzer is a cross-platform utility that uncovers the technologies used on websites. It detects content management systems, ecommerce platforms, web frameworks, server software, analytics tools and many more.
Wappalyzer can identify the presence of 14 common crypto-mining scripts.
These scripts include Coinhive, Crypto-Loot, JSECoin, ProjectPoi, and many more.
SIDENOTE. It’s not important to understand how each of these scripts differ. They all mine cryptocurrency and work in roughly the same way.
You can test Wappalyzer for yourself here.
Enter a domain and it tells you what technologies are being used on that website.
wappalyzer technologies ahrefs
looks like there are no cryptocurrency mining scripts present on Ahrefs.com. (Phew!)
But let’s get to the results, shall we?
We found 23,872 unique domains running cryptocurrency mining scripts.
As a percentage of the total 175M+ in Ahrefs’ database, that’s 0.0136%. (Or 1 in 7,353 websites.)
In terms of the actual crypto-mining script these sites are running, Coinhive is the most popular option by far. It accounts for 93.82% of our results—that’s ~22,396 websites.
(We’ll talk more about Coinhive later in the article.)
Let’s take a deeper look at our data to glean some additional insights.
1. How many monthly organic search visitors do these sites get?
Here’s a breakdown of the monthly organic search traffic distribution for these sites (as estimated by Ahrefs):
see the raw numbers for this graph here.
IMPORTANT! This IS NOT the total traffic; it’s estimated monthly organic search traffic. This means estimated search traffic from Google alone.
You can see that ~91% of websites that have crypto-miners installed are estimated to receive <50 visitors from Google each month—not many at all!
To summarise, most of the sites running crypto-scripts probably receive very little traffic.
We can only speculate as to why this is, but here are a few thoughts:
Abandoned websites may get hacked: I touched on this earlier. Basically, many people set up websites and then quickly lose interest. These websites are then abandoned and left to rot. Never do they have chance to attract a significant amount of traffic. Because they’re left abandoned, it’s likely that the CMS, theme, and plugin(s) won’t receive any critical updates. This leads to security flaws which in turn, make it easier for hackers to gain access and install crypto-malware. So, while an individual website might only be getting a few dozen visitors per month, hackers may be able to mine a significant amount of cryptocurrency should they hack into, and install crypto-mining scripts on, thousands of websites. (But again, that is a pure speculation, as we didn’t really dig into that.)
High-traffic have more to lose: Let’s assume you have a website with a ton of monthly search traffic; wouldn’t you avoid anything that may put your website at risk? Of course you would. There has even been rumours in the past that Google might block websites with crypto-mining scripts in Chrome (a browser with ~58% market share). Bottomline: installing crypto-mining scripts simply isn’t worth the risk for high-profile websites.