A Trojan is a malicious software or malware that disguises itself as legitimate or benign to deceive users.

The name “Trojan” is derived from the ancient Greek story of the wooden horse used to infiltrate Troy.

Similarly, Trojan horse malware appears harmless but contains malicious code hidden within.

Trojan Characteristics

1. Deceptive Appearance

Trojans often disguise themselves as legitimate software or files by using harmless names and icons.

Users may unknowingly download and install Trojans, believing they are installing legitimate applications.

2. Non-Self-Replicating

Unlike viruses or worms, Trojans do not self-replicate.

They rely on user actions, such as downloading and executing a malicious file, to spread.

3. Payloads and Malicious Actions

Trojans carry malicious payloads, the harmful actions they perform on the infected system.

The specific actions vary widely and can include stealing sensitive information, creating backdoors for remote access, modifying or deleting files, and more.

4. Backdoor Trojans

Backdoor Trojans create a secret entry point, or “backdoor,” on the infected system.

This allows attackers to gain unauthorized access, control the system remotely, and carry out various malicious activities without the user’s knowledge.

5. Downloader Trojans

Downloader Trojans focus on downloading and installing additional malicious software onto the infected system.

They act as a gateway for other types of malware, such as ransomware or keyloggers.

6. Banking Trojans

Some Trojans specifically target financial information.

Banking Trojans are designed to steal login credentials, credit card details, or other sensitive online banking and financial transaction information.

7. Remote Access Trojans (RATs)

Remote Access Trojans enable attackers to gain complete control over an infected system remotely.

Attackers can view, modify, or delete files, capture screenshots, record keystrokes, and perform other actions without the user’s knowledge.

8. Social Engineering

Trojans often use social engineering techniques to trick users into executing the malicious payload.

This can include deceptive emails, fake websites, or misleading advertisements encouraging users to download and run the Trojan.

9. Antivirus Evasion

Trojans may attempt to evade detection by antivirus software through various means, such as code obfuscation, polymorphic techniques, or encryption.

10. Prevention and Protection

To protect against Trojans, users should exercise caution when downloading files, avoid clicking suspicious links or email attachments, and keep their antivirus and security software current.

Trojans pose a significant cybersecurity threat, and their detection and removal often require specialized antivirus or anti-malware tools.

Regular software updates, cautious online behavior, and reputable security software contribute to an effective defense against Trojan attacks.