Describe various types of computer threats, their potential impacts and explain the preventive measures used to secure computer systems.

Threats break Confidentiality, Integrity or Availability. Write threat → impact → safeguard for full marks.

Threats and impacts:

1. Malware (virus/worm/Trojan/ransomware/spyware) — Deletes files, locks data for ransom, steals passwords. Impact: salary records lost, office halted.
2. Phishing — Fake bank/office links steal OTP/password. Impact: fund theft, account takeover.
3. Hacking — Password guessing, unpatched exploits. Impact: confidential farmer-subsidy data leaked/altered.
4. DoS/DDoS — Floods result/notice site. Impact: citizens cannot apply during deadline.
5. Insider/USB misuse + deletion — Pen-drive copy, accidental Shift+Delete. Impact: evidence loss, legal trouble.
6. Eavesdropping — Snooping open Wi-Fi. Impact: intercepted credentials.

Preventive measures:

1. MFA + roles — Strong passwords, OTP/biometric; clerk enters, officer approves; audit logs.
2. Firewall + IDS/IPS — Filter traffic; alert and block intrusions.
3. Antivirus + patching — Updated scanning; timely Windows/Office updates; scan USBs.
4. Email filter + training — Block .exe, verify sender; never share OTP.
5. Encryption + signature — HTTPS, hashed passwords, signed e-tender (ETA 2063).
6. Backup + drill — Offline full/incremental backup with restore test; SoC/CERT monitoring.

Close: layered people + technology + policy — single tool never enough.