Reading Time: 28 minutes There is a version of cryptocurrency mining that matters to anyone who runs a website, and it is not the version covered in the general explainers. It is what happens when someone else mines using your server, your hosting account, or the browsers of the people who visit your site, without you knowing and at your expense. It is called cryptojacking, and it has a specific profile that makes it unusually persistent. It does not steal data, so it does not trigger the alarms built for data theft. It does not deface anything, so nothing looks wrong. What it does is consume the processing capacity you are paying for, which surfaces as a site that has become mysteriously slow, a hosting bill that has moved, or an abuse notice from your provider that arrives as a surprise. We run hosting infrastructure, so this is something we deal with directly: detecting it, notifying customers about it, and occasionally suspending accounts because of it. This guide covers how it actually reaches a website, why it is hard to notice, what it costs beyond the electricity, how to detect it on your own site, and what to do if you find it. It also covers something most site owners have never read: what your hosting terms almost certainly say about mining, and why every provider prohibits it. That prohibition catches innocent people out, because an account mining without the owner's knowledge is still an account mining. What cryptojacking actually is Cryptojacking is the unauthorised use of someone else's computing resources to mine cryptocurrency. Palo Alto Networks describes it as silently consuming CPU cycles, increasing power costs and degrading system performance without overt signs of compromise, and notes that it is stealthy, scalable and difficult to detect in cloud and hybrid environments. The economics explain why it exists. Mining requires computation, computation requires hardware and electricity, and both cost money. If an attacker uses your server instead, their cost approaches zero and their margin becomes whatever they mine. They are not trying to damage you; they are trying to remain unnoticed for as long as possible, because every day undetected is profit. That incentive...
