Websites are using the power of your computer to tap into the current Bitcoin and cryptocurrency craze, hijacking your processor to 'mine' for coins while you are online.
It's called cryptojacking, and runs instantly when you go onto certain websites, with no real way to tell on the surface if your computer has been compromised for digital profit.
If it has been compromised, not only is your information at risk, but your computer could overheat and eventually wear down over time if you continually get attacked.
Even if you have never owned any Bitcoin or other cryptocurrency, your computer could still be used by hackers, as what they want from you is the power of your processor. With other people's computers working for them, hackers will then use an algorithm to find Bitcoin or other digital currencies anywhere in the world.
Back up, what exactly is Bitcoin again?
Bitcoin is a cryptocurrency. Twenty-one million of them were released in 2009 and they weren't worth much as they were pretty easy for tech savvy people to find.
But they're a finite resource. Think of them like gold. If there's a lot of gold being mined, the price isn't high. But inevitably, the world will run out of gold to find in the ground, so the price of it has risen.
The world was in the grip of the Global Financial Crisis, so many people had lost confidence in traditional markets. So purchasing a finite resource — such as bitcoin — made sense. And the price went up.
But once many of these Bitcoin were 'mined', it became much harder to find. It was easier to trade the coin in a more traditional way, so non-tech savvy people were buying the currency. And their value has now skyrocketed.
But I don't own Bitcoin. Why is my computer being attacked to find it?
Doesn't matter if you own Bitcoin or not. You've got a computer with processor. And that's power that computer hackers want to use to mine for bitcoin around the world.
These illegal cryptojacking operations need to build huge help to perform the algorithms needed to find the few Bitcoins left that aren't being traded on the open market. And they can't do that unless they build extremely expensive servers.
So they need to find more power on the cheap, which is why they're infiltrating websites that regular people visit all the time, and putting a script on there.
If you go to that website, your computer will be infected.
Websites such as Showtime, the official UFC streaming website and US political news website Politifacts.com were affected. Even in Australia, last month Subaru's official merchandise website became victim to one of these attacks.
While these attacks on websites are on the rise, websites are also putting the code in themselves as an extra way to earn money. One of the highest profile websites to do so has been The Pirate Bay, who has started to explore the idea as an alternative to advertising revenue.
The website copped a lot of slack after their trial of the software resulted in many users' computing power maxing out and heating up quickly when browsing.
Why are hackers attacking these sites?
Michael Dunworth, CEO of Wyre, a company which uses blockchain technology (the stuff behind Bitcoin) to transfer money same day internationally, told news.com.au that hackers are likely to look to these sorts of techniques for easy money.
"If you wanted to mine Bitcoin, you'd need a massive warehouse full of computers to have much success, so this is a much easier way for hackers to get access to cryptocurrency," he said.
The scripts are often placed on websites with outdated security, which hackers can easily scan, identify and then place their tools on without the site's owner or browsers even knowing.
Likewise, he said, it's much easier for a hacker to inject a script into a poorly designed website than to try and social engineer a hack into someone's Bitcoin wallet (where people often store their bitcoin).
Nick Savvides, CTO of Symantec Pacific Region, told news.com.au that these scripts take advantage of parts of the web browser that have access to the GPU to render images and videos very quickly and essentially re-purpose the GPU to mine coins instead.
If you are concerned about websites hijacking your computer's processor to mine for coins, Mr Savvides says the best thing you can do is keep your security software up to date.
"These tools will often block the code from running, the sites that run it and the sites that distribute it," he said.
"If you notice your computer getting very slow when browsing a site, it may be a sign that they are using a browser miner.
"Clear your browser cache and scan your computer for threats."
The coin most of the scripts use your processing power to mine for is called Monero, and is one of hundreds of cryptocurrencies like Bitcoin which are popping up everywhere.
The reason this coin is picked, rather than Bitcoin, is that it's the easiest coin to mine with a standard computer processor, rather than relying on expensive graphics units which most every day computers don't possess.
Why Bitcoin is today's gold
Think of Bitcoin as digital gold, it's mined like gold, there's a finite amount like gold, and the less gold there is left to find in the world, the higher its value. As Bitcoin is mined, people sell it on markets, where you buy it with "real world" currencies.
Because there is only a finite amount of Bitcoin, it means it's stored somewhere locally for you. Some people store theirs on their own computer's hard drive, which actually has led to many people losing millions of dollars worth by throwing out their drives.
These days, it's mostly stored on "virtual wallets", think of them like the iCloud of wallets.
However, these have been vulnerable to hacks in the past and millions of Bitcoins have been stolen.
The best method for storage is still up for debate from experts.
Can I mine my own Bitcoin?
Probably not. It's 2017, they've been around close to a decade and are now worth a fortune. It's not like they're lying around and can easily be found.
Bitcoin will only ever have 21 million coins available due to the algorithm in which it was created, meaning the less there are left to mine, the greater the value until it eventually reaches its peak.
Mr Dunworth's way of explaining it is to think of it like limited edition shoes. Nike might only put up 10 sets of new limited edition sneakers, if someone destroyed a shoe, there would only be 9 left and those 9 would be worth more and so on.
Like Bitcoin, when it first was released, there were 21 million, which were much easier to mine then and come across meant the value was much lower. Now, like the Jordans, as there are less and less Bitcoins to come across, value has skyrocketed.
Generally, the rate in which Bitcoins are available halves every four years, until eventually all 21 million have been found.
Years ago, to mine Bitcoin, you could have found some using your laptop in just a few hours, however these days due to the limited supply, it's much harder. If you wanted to make serious money off Bitcoin mining these days, you'd need to invest in massive networks of computers with powerful graphics processors running day and night to get anything resembling a profit — which is why hackers are harnessing the power of personal computers.
However, other digital currencies such as Monero can still be mined if you have just a high end consumer grade computer.
In these cases, if you have the right set up, you could mine almost a coin every couple of weeks, which at this stage has a value of about $300, and is increasing fast.
Coins like Monero and Ethereum are based on blockchain and have limited amounts like Bitcoin.
Hang on. Explain blockchain
Blockchain is basically a decentralised computer system which can govern how information is sent across the internet, and is essential to cryptocurrencies. By decentralised, we mean there is no single computer, but rather information is verified across millions of different computers across the globe.
While in the real world, I can just physically give you something and you now own it and I don't, it's not quite that simple digitally.
Think about when you send someone a photo over email, you're not really sending that photo itself, but creating a copy of it and sending that copy to someone. You both now have the photo. This wouldn't work in a currency world, because no real value is being sent.
So this is where the blockchain fits in, it allows people to send value (not just money) over the internet, by coming to an agreement on who owns it across millions of different computers.
Think of it like Paypal, who could be the middleman in governing that yes you did send $100 to James, and now you have $100 less and James has $100 more. But with blockchain, there is no central company or organisation that looks over this that could potentially tamper with it.
If you were to try and tamper with data on the blockchain, you'd need to do that somehow on all of the millions of computers in which the data needs to be verified across, making it an essentially unhackable way of sending goods.
This lays the backbone for Bitcoin and other digital currencies, as it allows them to have an intrinsic value, as you can create a finite number.
The blockchain will set up the agreement between its massive network that you sent those 2 Bitcoins to James, and that they are now his and you no longer have any ownership of them.
The blockchain itself has huge value not just for sending Bitcoin, but could be used to send anything of value — think the deed to real estate, the ownership of your car or even to verify information in databases to help thwart hacks.
While it currently is only really being talked about with Bitcoin, you'll be hearing a lot more about blockchain as it starts to become more important in all our digital lives.