ELI5: Explain Like I'm 5

Cache poisoning

Okay kiddo, imagine you have a secret treasure box in your room, and you always keep the key under your pillow. Your friend comes over and asks to borrow a toy, but while you're getting it, your friend sneaks a peek at the key under your pillow and remembers where it is. Next time you leave the room, your friend steals the key and uses it to open your treasure box and take whatever they want.

Cache poisoning is kind of like that. When you go on the internet, your computer saves little bits of information from the websites you visit in a "treasure box" called a cache. This makes going back to those websites faster next time because your computer already has some of the information it needs.

But sometimes, a bad guy called a hacker can sneak into your computer and change the information in your cache. They might do this by tricking your computer into thinking a website is something else entirely, so your computer saves the wrong information in your cache. Then, when you go back to that website, your computer uses the wrong information and it can cause all sorts of problems, like showing you fake information or stealing your personal information.

Just like you need to be careful who you show your key to, you need to be careful what websites you visit and make sure they are trustworthy. And if you ever think someone might have messed with your cache, you should tell a grown-up who can help you fix it.