What are the common computer security threats and protection measures?

Computer security threats break Confidentiality, Integrity or Availability of systems and data. Write each threat with its safeguard for full marks.

Common threats and protection:

1. Malware (virus/worm/Trojan/ransomware/spyware) — Deletes files or locks them for ransom. Safeguard: updated antivirus (signature + behaviour) and pen-drive scanning.
2. Phishing — Fake bank/office mail stealing passwords and OTPs. Safeguard: spam filter, verify sender, never share OTP.
3. Hacking via weak passwords/unpatched software — Unauthorized entry to marks/salary records. Safeguard: strong passwords + MFA and timely OS/app patching.
4. DoS/DDoS — Floods notice/result site so citizens cannot apply. Safeguard: firewall + rate limiting at network border.
5. Social engineering + insider misuse — Fake calls, USB data copy. Safeguard: staff training, role-based access with logs, and offline full/incremental backup with restore test.

Close: layered people + technology + policy — no single tool suffices.