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(see also trojan virus, trojan horse)

Trojan definition

A trojan is a type of malware that masks itself as a legitimate program or file so it can get inside a computer and perform malicious actions. Despite popular misconception, trojans are not viruses, since they cannot execute and replicate themselves — the user has to run the trojan (and thus give it the required system permissions) for it to activate.

Trojan examples

Backdoor trojans give remote access to a computer so hackers can execute commands, spy on data, and perform other malicious actions.

Banking trojans use keyloggers to steal your credit card information, passwords, and authentication details.

Stopping a trojan

  • Use an antivirus to stop malware from compromising your device. Antiviruses can identify infected files, quarantine them from the rest of the system, and safely extract the malicious code.
  • Update your software regularly to patch newly discovered security flaws. This includes your operating system — don’t keep snoozing those critical security updates forever.
  • Avoid suspicious links in emails or text messages, whether from strangers or friends. Compromised accounts spread the infection by spamming the victim’s contacts with messages intent on tricking them to download the malware.
  • Avoid unknown or unexpected attachments because they may harbor trojans. If possible, scan any attachment with NordVPN’s Threat Protection feature or a reputable antivirus.
  • Avoid potentially dangerous sites (like underground torrent repositories) because they may automatically try to infect your device. NordVPN’s Threat Protection feature keeps an up-to-date list of malicious websites and stops you from entering them by accident.

Watch it explained: Trojan and other terms