what is trojan horse in computer

A Trojan horse in computer security is a type of malware that looks like safe software but secretly does harmful things once you run it. It does not spread by itself like a virus; it usually depends on tricking you into opening a file, clicking a link, or installing a fake app.

How it works

• It disguises itself as something useful, such as a free program, email attachment, or update.

• After it gets into the device, it may steal passwords, spy on activity, damage files, or give attackers remote access.

• It often spreads through social engineering, meaning it relies on deception rather than automatic self-replication.

Simple example

A file named like a photo editor might actually contain a Trojan. If you install it, the program may open normally at first, but behind the scenes it could start collecting data or opening a backdoor for an attacker.

How to stay safe

• Download apps only from trusted sources.

• Avoid opening unexpected attachments or links.

• Keep your system and security software updated.

• Use strong, unique passwords and enable extra login protection where possible.

In short, a Trojan horse is malware that pretends to be legitimate so you let it in yourself.