Network security
OCR GCSE Computer Science revision on Network security. Aligned to the OCR GCSE Computer Science J277 specification. This bank has 8 practice questions on this topic.
Sample questions (3 of 8)
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Question 1
A 'phishing' attack is best described as...
- A) Software that secretly records keystrokes
- B) Tricking someone into giving up information via a fake message
- C) Flooding a server with requests to take it down
- D) Encrypting files for ransom
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Answer: Tricking someone into giving up information via a fake message
Phishing uses convincing-looking emails or texts pretending to be from a bank, school, or service — link goes to a fake login page that captures the password. Spear-phishing targets a specific person; whaling targets executives. Defences: don't click suspicious links, hover to check the URL, look for HTTPS + correct domain.
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Question 2
A DoS (Denial of Service) attack works by...
- A) Stealing user passwords
- B) Overwhelming a server so legitimate users can't use it
- C) Installing a hidden listener
- D) Modifying database records
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Answer: Overwhelming a server so legitimate users can't use it
DDoS (Distributed) = the same but coming from THOUSANDS of compromised machines (a botnet) at once, making it much harder to block. Defences: firewall, rate limiting per IP, content-delivery networks like Cloudflare that absorb the traffic, IP blocklists.
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Question 3
A brute-force attack on a password works by...
- A) Asking the user for it
- B) Trying every possible combination until correct
- C) Encrypting the password
- D) Sending it back to the user
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Answer: Trying every possible combination until correct
An 8-character password from 96 possible characters = 96^8 ≈ 7 quadrillion combinations. Modern GPUs can try billions per second. Defences: long passwords (length matters more than complexity), account lockouts after N attempts, multi-factor authentication, rate limiting, password hashing with bcrypt/argon2 (deliberately slow to compute).
Want to test yourself on the remaining cards for this topic?
5 more questions on Network security — plus mistakes tracking and spaced repetition across the whole Computer Science spec.