Trojan Horse

A trojan horse is malware that pretends to be something useful, such as a game, crack, invoice or software update, to persuade a user to install it. Once running, it carries out hidden actions such as stealing data or opening a backdoor.

Why it matters

Trojans do not replicate on their own, so their success depends on deception. They are a common delivery method for remote access tools, banking credential stealers and ransomware loaders. Downloading software only from official sources removes most of the risk.

Variants include remote access trojans, banking trojans that steal financial logins, and droppers that download further malware after the first infection.

Example

A user downloads a free video converter from a random website. It works, but also installs a background process that logs keystrokes and sends them to a remote server.

Common mistakes

• Downloading cracked software or from unofficial mirrors.
• Ignoring operating system warnings about unsigned or unknown publishers.
• Running everyday work with administrator rights, which lets a trojan do more damage.

Related

• Malware
• Social engineering
• Least privilege

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