Your Processor Goes Brrrr… and Leaks Sensitive Data!!
Imagine you’re super careful about your data security. You only run trusted apps and software on your phone or computer, and you make sure they’re free of bugs. You’d think your data was completely safe, right? Well, not quite. Even if the software you use is flawless, modern processors, the brains of your devices—can still make mistakes. In order to run faster, they try to “guess” what might happen next (this is called speculative execution). Sometimes, they guess wrong, which might give them access to information they aren’t supposed to handle, like passwords or private. Even though this access is brief, it can still leak information through very sneaky side effects, which are called side-channels.
So, what is a side-channel? One simple example involves the time it takes your device to do things. Imagine you’re opening a locked box, and depending on how long it takes you, someone could guess whether the box was already unlocked or not. In computers, attackers can measure how long it takes the processor to retrieve data from its memory. By studying these tiny differences in time, they can figure out what kind of information is being accessed, even without directly touching it.
In 2018, researchers discovered two major security flaws, Spectre and Meltdown, that let attackers take advantage of this guessing behavior, in virtually all processors used in mobiles, desktops, and tablets, manufactured in the last 20 years by Intel, AMD, Apple, Qualcomm, IBM, etc.
Spectre tricks the processor into accessing data it shouldn’t by misleading the system’s guessing mechanism, while Meltdown takes advantage of a weakness in how certain processors separate user data from critical system data. Both allowed attackers to peek at sensitive information, like passwords or browser cookies, even if they weren’t supposed to have access.