Linux

"A rootkit is a collection of computer software, typically malicious, designed to enable access to a computer or an area of its software that is not otherwise allowed (for example, to an unauthorized user) and often masks its existence or the existence of other software."

That's the Wikipedia definition, in CompTIA Security+ the concept of the malware masking itself is quintessential to the definition of a rootkit. I hear this shit all the time from people on here who think anything that gets elevated privileges is a "rootkit" and hasn't the slightest idea what the fuck they're talking about.

"But you don't know if it could install a backdoor!"

You don't know if half the shit you install is doing that either, or is Easy Anticheat known for doing this in some official investigation? Did someone find out that Activision is deploying malware in ricochet?

If not, you're operating on suspicion that you don't harbor for other software without evidence, based purely on things you've probably just barely heard about.