What is the main purpose of a Trojan horse in network and information security?

Question

What is the main purpose of a Trojan horse in network and information security?

1. A. To block network traffic by overwhelming servers
2. B. To steal or delete files and create a backdoor for hackers (Correct answer)
3. C. To silently copy itself to other systems using network vulnerabilities
4. D. To intercept network traffic by flooding communication channels

Correct Answer

Option B — To steal or delete files and create a backdoor for hackers

Detailed Solution & Explanation

The correct answer is To steal or delete files and create backdoors.

Key Points

• A Trojan horse disguises itself as legitimate software so the user installs it willingly; once running it performs hidden malicious actions — stealing or destroying data and opening a backdoor for remote access.
• Its defining trait is deception, not self-replication.
• The distractors describe other malware: overwhelming traffic is a DoS attack, self-copying to other files is a virus or worm, and intercepting traffic is a man-in-the-middle attack or sniffer.

Additional Information

• The key distinction in this family: a virus attaches to a host file and needs a user action to spread; a worm self-replicates across networks unaided; a Trojan does not self-replicate at all.
• Other categories: ransomware (encrypts data for payment), spyware (covert monitoring), keylogger (records keystrokes), rootkit (conceals its own presence), adware and botnets.
• The name comes from the Greek stratagem at Troy — the danger lies in what is concealed inside something apparently harmless.
• Trojans are typically delivered through email attachments, pirated software and malicious downloads, which is why user awareness matters as much as antivirus software.