📝 Passwords and User Authentication

📖 From Operating System • 15. Security • 10 questions available

Practice MCQs for Passwords and User Authentication. Test your knowledge with carefully crafted questions across easy, medium, and hard difficulty levels.

🔄 Last updated: 2026-07-27

Easy Questions

Medium Questions

Hard Questions

📝 Sample Questions

Q1. A user inserts a new USB flash drive into a computer that is infected with a boot‑sector virus. Which of the following actions is most likely to prevent the virus from infecting the removable disk?

🔹 A. Disable the operating system’s auto‑run feature for removable media

🔹 B. Increase the computer’s RAM size

🔹 C. Change the BIOS clock to a future date

🔹 D. Use the disk as a read‑only device without any write protection

💡 Difficulty: easy | ✅ Correct: A

Q2. Why does an encrypted virus include decryption code that runs before the payload?

🔹 A. To hide its code from signature‑based scanners by storing encrypted bytes that are only visible after decryption at runtime

🔹 B. To increase its execution speed

🔹 C. To reduce memory usage

🔹 D. To allow it to infect only encrypted files

💡 Difficulty: medium | ✅ Correct: A

Q3. A boot‑sector virus copies the original boot sector to an unused location X and replaces the active boot block. Which forensic step is most likely to reveal the infection?

🔹 A. Scan only the active boot sector with antivirus

🔹 B. Reformat the disk without analysis

🔹 C. Compare the contents of the active boot sector, the copy at location X, and a known good boot sector; look for discrepancies and unexpected executable code

🔹 D. Check only the operating system logs

💡 Difficulty: hard | ✅ Correct: C

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🔗 Related Topics

📝 The Security Problem in Operating System 📝 Program Threats in Operating System 📝 Trojan horse 📝 Trap door 📝 Logic bomb

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