Trojan

The name refers to the Trojan Horse: a trojan poses as harmless software but hides malicious functions. Once run, it can steal passwords, open a backdoor, download more malware ✕ Malware (from "malicious software") is the umbrella term for any harmful software — viruses, trojans, ransomware, spyware — that damages, spies on, or hijacks devices. More in the glossary → , or remotely control the device. Unlike a virus, it doesn't replicate itself — it relies on a user being tricked into installing it, for example through a fake download. You're protected by only downloading from trusted sources and using an antivirus ✕ An antivirus is a program that detects, blocks and removes malicious software. Modern ones combine known signatures with behavior analysis. More in the glossary → with real-time protection ✕ Real-time protection watches the system continuously and blocks threats the instant they appear, not just during a manual scan. More in the glossary → . See the best antivirus comparison.