Cyber Security — SSC CGL Computer Knowledge
SSC's security questions are a matching exercise: a one-line behaviour ("encrypts your files and demands money") and four names. Learn the threat glossary, the defence glossary, and two India-specific facts (IT Act 2000, CERT-In) — that is the entire syllabus. As a bonus, it is also the actual survival kit for a desk job in a government office.
1. What SSC actually asks
Tier 2, Section III: 2–4 of the 20 questions. Formats: "X is a type of…" (malware taxonomy), "emails pretending to be your bank are called…" (attack names), "which of these protects…" (defences), and occasionally the IT Act year or CERT-In's role.
2. Malware — the threat glossary
| Name | Behaviour (the exam's one-liner) |
|---|---|
| Virus | Attaches to files/programs; spreads when the host runs |
| Worm | Self-replicates across networks without a host file or user action |
| Trojan horse | Disguises itself as legitimate software; opens a backdoor |
| Ransomware | Encrypts files and demands payment (WannaCry, 2017) |
| Spyware | Secretly collects your information |
| Keylogger | Records keystrokes to steal passwords |
| Adware | Floods you with unwanted advertisements |
| Botnet | Network of infected "zombie" machines controlled remotely |
The virus/worm distinction is the most-asked line in the table: a worm needs no host and no human click.
3. Attacks on people — phishing and cousins
- Phishing — fraudulent emails/websites impersonating trusted organisations to steal credentials.
- Vishing — the same con by voice call; smishing — by SMS.
- Spoofing — forging an identity (sender address, caller ID, website).
- Man-in-the-middle — attacker secretly relays/alters communication between two parties (why public Wi-Fi + banking is a bad pair).
- Denial of Service (DoS) — flooding a server with traffic so real users can't reach it; DDoS = the flood comes from a botnet.
- Brute force — trying every password combination until one works.
- Social engineering — the umbrella term: manipulating people rather than machines.
4. Defences
- Antivirus — detects and removes malware; must be kept updated (new signatures).
- Firewall — filters network traffic between a trusted network and the outside; can be hardware or software.
- Encryption — scrambles data so only key-holders can read it; HTTPS/padlock = encrypted browsing.
- Two-factor authentication (2FA) — password plus a second proof (OTP, authenticator app); the single best account upgrade.
- Strong passwords — long, mixed character types, unique per site; never shared, never on sticky notes.
- Backups — the working antidote to ransomware; regular, offline/cloud copies.
- Updates/patches — close the security holes malware exploits (WannaCry hit unpatched systems).
- Digital signature — cryptographic proof of a document's authenticity and integrity (legally valid in India).
5. Hackers and Indian framework
- White hat — ethical hacker, tests security with permission; black hat — criminal; grey hat — in between (no permission, no malice).
- IT Act, 2000 — India's law on cybercrime and electronic commerce (major amendment: 2008); gives digital signatures legal standing.
- CERT-In — the Indian Computer Emergency Response Team (under MeitY): the national nodal agency for responding to cyber-security incidents.
- Cyber Swachhta Kendra — MeitY's botnet-cleaning and malware-analysis centre.
- Cookies — small files websites store in your browser to remember you; not malware, but a privacy consideration.
6. Solved PYQ-style examples
Q1. Malware that encrypts a victim's files and demands payment is: Solution. Ransomware (WannaCry, 2017, is the exam's stock example).
Q2. Fraudulent emails that appear to come from your bank, asking you to "verify" your password, are an example of: Solution. Phishing — impersonation by email. (By phone it becomes vishing; by SMS, smishing.)
Q3. Which of the following self-replicates across a network without attaching to a host file? Solution. Worm — the no-host, no-click property is exactly what separates it from a virus.
Q4. A system that monitors and filters incoming and outgoing network traffic is a: Solution. Firewall — the barrier between a trusted network and the untrusted internet.
Q5. India's IT Act was enacted in the year: Solution. 2000 (major amendment in 2008).
7. Exam protocol
- Learn the malware table as behaviour → name one-liners; the question quotes the behaviour almost verbatim.
- Phishing family by channel: email = phishing, call = vishing, SMS = smishing.
- Defences match threats: ransomware → backups, weak passwords → 2FA, network attacks → firewall, malware → updated antivirus.
- Two India facts cold: IT Act 2000; CERT-In = national incident-response agency.
- With −1 negatives on a qualifying module, answer the glossary matches you know and skip genuine unknowns.
