Stretch tasks Networks and Network Security

Round 1: Quiz Blitz

1. Each connects to several or all of the others That gives many possible routes.
2. Traffic reroutes around a failure There is no single point of failure.
3. It is expensive and complex to cable Every extra connection is more cable.
4. router A switch joins devices within one LAN.
5. False SMTP sends. IMAP retrieves.
6. IP TCP splits and reassembles. IP addresses and routes.
7. Trying every possible password until one works Length makes it impractical.
8. Flooding a server so it cannot serve real users Legitimate users are crowded out.
9. Validating inputs Rejecting or escaping input stops it reaching the database as SQL.
10. Inventing a scenario to persuade someone to hand over information It is a form of social engineering.
11. Long passwords; Locking an account after failed attempts More combinations, and fewer chances to try them.
12. True HTTP, TCP and IP carry on unchanged.

Round 2: Quick Fire

1. • A star is cheaper, but its switch is a single point of failure
   • A mesh reroutes around failures, but is expensive to cable
   Model answer

   A star needs less cable, so it is cheaper, but the central switch is a single point of failure. A mesh has many routes, so traffic reroutes around a failure, but all those connections make it expensive and complex to cable.

2. • SQL typed into an input box is passed to the database
   • Validating inputs stops it
   Model answer

   An attacker types SQL into an input box, such as a login form, and the site passes it straight to its database, which runs it and reveals or destroys data. Validating inputs, rejecting or escaping anything that could be SQL, prevents it.

3. • Captured data is scrambled and unreadable
   • Without the key
   Model answer

   Encryption cannot stop an attacker capturing the data as it travels. But the captured data is scrambled, so it is unreadable and useless without the key.

4. • It floods a server with requests
   • Real customers cannot get in, so sales and reputation suffer
   Model answer

   A denial of service attack floods a server with so many requests that it cannot serve legitimate users. Customers cannot reach the business's website, so it loses sales and damages its reputation.

Round 3: Big Think

1. • Phishing: train staff to recognise fake emails
   • Two-factor authentication, so a stolen password is not enough
   • Brute force: a long, strong password
   • Lock the account after a few failed attempts
   • So trying every combination becomes impractical
   • SQL injection: validate the input
   • So the database never runs what an attacker types
   • Further layers such as access levels or updates
   Model answer

   For phishing, the shop should train staff to recognise fake emails and never enter details through a link, and use two-factor authentication so a stolen password alone is not enough. For the brute force attack, the admin account needs a long, strong password, and the login should lock after a few failed attempts, which makes trying every possible combination impractical. For SQL injection, the search box should validate its input, escaping or rejecting anything that could be SQL, so the database never runs what an attacker types. User access levels should also limit what each account can reach, and regular updates close known weaknesses.

2. • A star gives each device its own cable, so it is fast and one break affects one device
   • But the star's switch is a single point of failure
   • A mesh reroutes around failures
   • But a mesh is expensive and complex to cable
   • Wired is faster, consistent and more secure
   • Wireless lets laptops move and is cheap to install
   • But wireless suffers interference and needs encryption
   • A justified conclusion, such as a mixture
   Model answer

   A star gives each device its own dedicated cable to a switch, so it is fast and one broken cable affects only one device, but the switch is a single point of failure. A mesh reroutes traffic around any failure, so it is very resilient, but cabling every connection is expensive and complex. Wired connections are faster, more consistent and more secure, because an attacker needs physical access, which suits classroom desktops. Wireless lets laptops and tablets move between rooms and is cheap to install, but it is slower, suffers interference and is less secure, so it must use encryption such as WPA3. Overall, a star with wired desktops and wireless access points for portable devices is the best combination for a school.

This or That

1. A full mesh In a star the switch is one. A mesh reroutes around failures.
2. A star A full mesh needs a connection between every pair of devices.
3. A brute force attack Phishing tricks a person. Brute force simply tries every combination.
4. Phishing Pretexting invents a scenario, often over the phone. Phishing sends a message that impersonates an organisation.
5. Validating inputs A firewall filters traffic, but the SQL arrives inside an ordinary web request.
6. No: it blocks traffic Anti-malware removes malware. A firewall blocks traffic that is not permitted.
7. HTTPS HTTPS is HTTP with encryption, so intercepted traffic cannot be read.
8. Length Each extra character multiplies the number of combinations to try.

Memory Match

• A 6 Mesh topology: Devices linked to several others
• B 3 Brute force attack: Trying every possible password
• C 1 Denial of service: Flooding a server with requests
• D 5 SQL injection: Database commands typed into an input box
• E 4 Pretexting: Inventing a scenario to get information
• F 2 Firewall: Blocks traffic that is not permitted

Sort It

1. Social engineering A phishing email pretending to be from a bank It tricks the person, not the technology.
2. Technical attack Flooding a server with requests That is denial of service.
3. Social engineering A caller invents an urgent story to get a password That is pretexting.
4. Protection Validating every input This prevents SQL injection.
5. Social engineering Watching someone type their password That is shouldering.
6. Protection A firewall blocking unpermitted traffic A firewall is a protection.
7. Technical attack Trying every possible password That is a brute force attack.
8. Technical attack Capturing data on open Wi-Fi That is data interception.
9. Protection Encrypting data in transit Intercepted data cannot be read.
10. Technical attack Typing SQL into a search box That is SQL injection.
11. Protection Penetration testing with permission It finds weaknesses before attackers do.
12. Protection Locking accounts after failed logins This defeats brute force.