A Trojan, or Trojan horse, is a type of malware that disguises itself as legitimate code or software. It is designed to deceive users into loading and executing the malware on their device, often by appearing as a legitimate application or file. Once installed, a Trojan can perform the action it was designed for, such as stealing sensitive data, taking control of the users computer, or setting up backdoor access points to the system. Unlike computer viruses and worms, Trojans generally do not attempt to inject themselves into other files or otherwise propagate themselves).
Trojans are generally spread by some form of social engineering, such as by duping a user into executing an email attachment disguised to appear innocuous or by clicking on a fake advertisement on social media). There are various kinds of Trojans, and depending on the criminal programmers intent, a Trojan can act as a standalone malware or as a tool for other activities, such as delivering future payloads or communicating with the hacker at a later time. Some common threats that come from Trojans include:
- Banker Trojan: Designed to target users banking accounts and financial information, attempting to steal account data for credit and debit cards, e-payment systems, and online banking systems.
- Distributed denial-of-service (DDoS) Trojan: Designed to launch DDoS attacks on targeted websites or networks.
- Trojan-Spy programs: Designed to spy on how the user is using their computer, such as by tracking the data entered via the keyboard, taking screenshots, or harvesting email addresses.
It is important to note that a Trojan is not a virus, as viruses can execute and replicate themselves, while a Trojan cannot. A user has to execute Trojans, and even so, Trojan malware and Trojan virus are often used interchangeably. To protect against Trojans, users should be cautious when opening links or attachments in emails, avoid downloading files from untrusted sources, and keep their antivirus software up to date.
