A Trojan, or Trojan Horse, is a type of malware which disguises itself as legitimate code or software to mislead the user.

Characteristics of a Trojan

Trojans do not self-replicate like worms or other viruses. Instead they depend on social engineering techniques to trick users into executing the malicious software.

Common methods include disguising the Trojan as a software update, or as an email attachment.

Once the Trojan has been executed it can perform a number of malicious activities, including:

  1. Backdoor Access: Trojans create a backdoor on the infected system, allowing cybercriminals to remotely access and control the device. Once they have control of the device they can use it for further exploitation or the installation of additional malware.
  2. Data Theft: Trojans can be designed to collect sensitive information such as usernames, passwords and credit card information. The information is usually gathered by using keylogging or screen capturing.
  3. Resource Exploitation: Some Trojans can hijack system resources and use the systems to mine cryptocurrency or carry out a DDoS attack.
  4. Spyware: Some Trojans can monitor user activity and collect personal information without the user’s knowledge.

Types of Trojan

There are various types of Trojan which can be categorized based on their intended functions:

  • Remote Access Trojans (RATs): Attackers can control an infected device remotely.
  • Banking Trojans: These are specifically designed to steal financial information by targeting online banking sessions, intercepting credentials and transactions.
  • Ransomware Trojans: These are used to encrypt files on an infected device/system and demand a ransom for decryption.
  • Trojan Downloaders: These Trojans are designed to download and install additional malware on the infected device.

Preventing Trojan Infections

Preventing Trojan infections involves a combination of user awareness, comprehensive security practices and proactive software.

Key strategies include:

  1. Education and Awareness: Users should be educated about the risks of downloading files or clicking on suspicious links. Reminding employees to be wary of potential social engineering techniques can help decrease the likelihood of infections.
  2. Comprehensive Cybersecurity Plan: Using security software can help detect and block Trojans. Building a layered approach to cyber defenses is key to defending against evolving, sophisticated cyberthreats.
  3. Regular Updates: It is essential to ensure operating systems and applications are updated regularly.
  4. Safe Browsing Habits: Safe browsing should be practiced by all users including avoiding untrustworthy websites and ensuring software is only downloaded from reputable sources.