Trojan

What is a Trojan?

Trojans are malicious programs that misrepresent themselves to appear routine or helpful, but actually carry out hidden functions.

How Trojans spread

Trojans frequently spread via email, pirated software applications, license key generators (Photoshop is a grand favorite), drive-by downloads, and phishing attacks. One of the most dangerous Trojans was Zeus, a banking Trojan, which stole confidential banking information. Zeus spread on both computers and mobile devices, and was reported to have infected millions of users and stolen millions more from private and corporate banking accounts. Trojans also frequently install backdoors that allow computers to be remotely controlled, either directly or as part of a botnet.

Known cases

The Zeus Trojan was one of the most successful malware created, having stolen approximately 47 million dollars. Other notable cases include Shedun, which at its height, infected approximately 2000 users per day, and Tiny Banker Trojan, which as its name suggests, is one of the smallest Trojans ever created and therefore difficult to detect.

How to block Trojans

To guard against Trojans, we recommend being vigilant as to what email attachments you open and what web links you click on. And of course, Avira Free Antivirus protects you from Trojans.

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The Avira Security Wordbook

Search our threat glossary for clarifications on frequently used terms in IT security.