CSC2203 · Network Security

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CSC2203 · Network Security

Security Practice Lab

Independent Study — auto-marked, full syllabus Weeks 1–10 · out of 100
Score: 0 / 100
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How this lab works

This is your hands-on practice space for the whole CSC2203 syllabus — all ten weeks of the official course outline, from Week 1 foundations through Week 10 risk & review. Weeks 1–4 rebuild what you've already been taught as something you do instead of read: classify a real-feeling incident, run a flood attack against a capacity meter, break a weak cipher, watch a hash avalanche, run RSA by hand. Weeks 5–10 are a structured first look ahead — built from the course textbooks — at authentication & access control, Kerberos & PKI, secure protocols, email/app-layer security & firewalls, intrusion detection, and risk & vulnerability assessment, so you arrive at each of those lectures already having met the core ideas once.

Each module has two parts. The regular cards are Practice — sandboxes and tools with instant feedback, ungraded, as many tries as you like. Near the end of each module is a gold-bordered Assessed Challenge — personalised to you, worth 10 of your 100 final marks. Answer every question, then click "Check my score" — nothing is marked right or wrong while you're still answering. Your score appears along with which ones you got right and wrong, and you can try again with a freshly reshuffled set of questions as many times as you like; your best attempt is what counts toward your final mark. Use the practice tools first to work out the mechanics, then apply what you learned in the assessed challenge.

This is graded, sequential, and locked. Every assessed challenge is personalised from your name and Student ID, so your questions and numbers won't match a classmate's — copying an answer from someone else won't work. Each assessed challenge can be submitted once and locks immediately after. Modules unlock in order — you cannot open Module N+1 until Module N's assessed challenge has been submitted, so pace yourself; this is designed as a running independent study over several weeks, not a single sitting. Your certificate unlocks only once all ten modules are submitted.
Browser note: the hashing module uses your browser's built-in cryptography engine (Web Crypto). This works in any current version of Chrome, Edge, Firefox or Safari — no install needed. If a hash box stays empty, try a different browser.

What each module covers

ModuleWeekYou willAssessed marks
1 · FoundationsWk 1Classify CIA violations, the threat chain, and authentication vs. authorization10
2 · Network AttacksWk 2Identify malware, run a DoS-vs-DDoS simulator, spot spoofing/recon, scan a mock host, trace NAT10
3 · Symmetric CryptoWk 3Calculate key spaces; run an XOR cipher; break a reused key10
4 · Hashing & Public-KeyWk 4Trigger the avalanche effect; watch ECB vs. CBC; run RSA by hand10
5 · Authentication & Access ControlWk 5Compute password entropy; tell MAC from DAC and RBAC from ABAC10
6 · Kerberos & PKIWk 6Step through an AS/TGS ticket exchange; trace a certificate chain of trust10
7 · Secure ProtocolsWk 7Step through a TLS handshake; compare IPsec AH vs ESP10
8 · Email, App Security & FirewallsWk 8Test firewall rules against simulated packets; match OWASP Top 10 categories10
9 · Intrusion Detection & MonitoringWk 9Triage a mock alert stream; tell signature- from anomaly-based detection10
10 · Risk, Assessment & ReviewWk 10Score a risk matrix; diagnose an incident that ties the whole course together10
Total100

Weeks 5–10 are enrichment/preview material built from the course textbooks ahead of those lectures — if something you meet here differs from how your lecturer later presents it in class, the lecture takes precedence.

Week 1 Foundations

Module 1 — CIA, threats, and the Asset→Control chain

For each incident below, work out (a) which CIA objective was hit hardest, (b) whether it's a passive or active attack, and (c) where the vulnerability actually sits. Submit means recording your reasoning in the worksheet — use these as practice first.

Authentication vs. authorization — the most confused pair in the course

Authentication proves who you are. Authorization decides what you're allowed to do once you're recognised. Both can succeed, both can fail, or one can succeed while the other fails — that last case is the one people mix up.

🎯 Assessed challenge · 10 marks ⏱ Estimated time: ~15 min

Your personalised incidents

New incidents, different from the practice ones above. Answer all of them, then check your score — you'll see what's right and wrong and can try again with a fresh set.

Written task (for your worksheet)

Pick one of the five incidents above and walk it through the full Asset → Threat → Vulnerability → Attack → Risk → Control chain from Week 1, in your own words. Draft it here — this text stays in your browser only, so copy it into your worksheet when you're happy with it.

Week 2 Malware & Network-Layer Attacks

Module 2 — Malware, DoS/DDoS, spoofing, reconnaissance & NAT

Everything here is simulated against a fake, harmless target — no real scanning, flooding or spoofing tool is used or should ever be pointed at a system you don't own. The goal is to see the shape of each attack clearly enough that you'd recognise it in a log file.

Malware taxonomy — name that nasty

Different malware families are grouped by how they spread and what they do, not by how dangerous they sound.

DoS vs. DDoS — simulated botnet takedown

A botmaster commands a botnet — a network of previously-compromised devices, often recruited through phishing or an unpatched vulnerability — to flood a target at once. Watch what an undefended target looks like below, then switch to the defender's seat and see what mitigation actually does. Every "bot" and "target" here is a fictional icon on this page; nothing controls a real device.

SIMULATION — every "bot" and "target" here is a fictional icon on this page. Nothing controls a real device.
Target capacity100%
Requests/sec hitting target: 0 Status: Online

Spoofing & reconnaissance

Two attacker moves that usually happen before the main attack: forging where traffic appears to come from, and quietly mapping what's reachable.

Reconnaissance in practice — scan a mock host

This is a fabricated host that exists only on this page. Click a port to "probe" it the way a reconnaissance scan would, one port at a time.

Click a port above to probe it.

NAT — watch the translation table fill in

A NAT box maps ⟨internal IP, internal port⟩ to ⟨external IP, external port⟩ so many private-network machines can share a small number of public addresses. Add a few simulated connections and watch the table build.

Internal hostInternal ⟨IP:port⟩NAT-assigned external ⟨IP:port⟩Destination

Notice every row leaves through the same external IP, distinguished only by port — this is exactly why a single public IP address can serve an entire office or campus.

🎯 Assessed challenge · 10 marks ⏱ Estimated time: ~20 min

Malware, attack reasoning & your personal NAT calculation

The NAT question uses numbers assigned to you — work it out the same way you just did in the demo above.

Week 3 Symmetric-Key Crypto

Module 3 — Key spaces, XOR, and why key reuse breaks everything

Feel the difference between a 56-bit key and a 128-bit key, then reuse an XOR key badly on purpose so you can see exactly what an attacker gets for free when you do.

Brute-force key-space calculator

Computational difficulty is the whole point of a key-length choice. Compare DES's 56-bit key against AES-128 and AES-256.

Choose a key length and press Calculate.

Watch a weak key actually get brute-forced

The calculator above tells you how long a brute force would take. Here's one actually happening: an 8-bit XOR key (just 256 possibilities) being tried one at a time against a captured ciphertext, using a known-plaintext assumption — exactly how many real key-recovery attacks work.

Captured ciphertext (hex)
—
Trying key
0x00
Decrypted attempt
........
Keys tried: 0 / 256 Elapsed: 0 ms Rate: —

XOR cipher — encrypt, decrypt, then break your own reused key

First confirm XOR is symmetric (the same operation encrypts and decrypts). Then reuse the same key on two different messages — a genuine "two-time pad" mistake — and see what leaks with no key-cracking at all.

Enter a message and key, then press the button.

Two messages, one reused key — press the button to see what an eavesdropper recovers without ever finding the key.
🎯 Assessed challenge · 10 marks ⏱ Estimated time: ~20 min

Your personalised key space & XOR ciphertext

The XOR field below is pre-filled into the practice tool above with your assigned plaintext and key — click "Encrypt & decrypt" up there, then copy the ciphertext hex down here.

Week 4 Hashing & Public-Key

Module 4 — Avalanche effect, ECB vs CBC, RSA, and signatures

Four exercises, each rebuilding a slide from Week 4 as something you operate yourself instead of watch.

SHA-256 avalanche sandbox

Hash a string, flip one character, hash it again. A secure hash should change roughly half its output bits — with no visible relationship to what changed.

Press "Compute SHA-256" to begin.

Plain hash vs. HMAC — which one can an attacker forge?

A message ships with an integrity value. An attacker who can read the wire tampers with the message. Can they still produce a value that looks valid — without knowing the secret key?

Press the button to see both values for the original message.

ECB vs. CBC — watch the pattern leak

Both use the same simplified teaching cipher (an XOR-based substitution — not real AES, so the arithmetic stays checkable by hand). The plaintext below is deliberately repetitive, like a bitmap image or a form with fixed fields. Encrypt it block-by-block under ECB, then under CBC, and compare.

Plaintext (identical shapes repeat on purpose)

ECB ciphertext — every identical plaintext block still looks identical

CBC ciphertext — each block is XORed with the previous ciphertext block first

RSA sandbox — generate keys, encrypt, decrypt, sign, verify

Real RSA uses primes hundreds of digits long; we use tiny primes here so every step is checkable by hand, exactly like the worked example from lecture.

Choose a prime pair and press "Generate keypair".
Generate a keypair first.
Generate a keypair first.
🎯 Assessed challenge · 10 marks ⏱ Estimated time: ~25 min

Your personalised RSA keys, plus HMAC & ECB/CBC reasoning

The RSA sandbox above has been pre-set to your assigned prime pair, message M and hash-value H. Generate the keypair, run encrypt/decrypt and sign/verify up there, then transcribe n, C and S down here.

Week 5 Authentication & Access Control

Module 5 — Proving who you are, and deciding what you can do

Two separate problems: authentication (proving identity — something you know/have/are) and access control (once identity is established, what you're permitted to do). This module previews both ahead of lecture.

Password entropy calculator

Entropy in bits ≈ length × log₂(character-set size). A larger, more varied character set and more characters both push an attacker's expected guessing time up exponentially — this is the same "computational difficulty" idea from Week 3's key-space calculator, applied to passwords instead of keys.

Choose a length and character set, then press Calculate.

Access control models — quick check

Four models, four very different rulebooks for "who can do what."

🎯 Assessed challenge · 10 marks ⏱ Estimated time: ~15 min

Your personalised entropy calculation & access-control scenario

The entropy question uses a length and character set assigned to you — work it out the same way as the practice tool above.

Week 6 Kerberos & PKI

Module 6 — Trusted third parties: tickets and certificates

Two ways a network lets strangers trust each other without sharing a secret in advance: a ticket-granting service (Kerberos) and a chain of digital signatures (PKI) — reusing the public-key mechanics from Week 4.

Kerberos — step through the ticket exchange

Click through each step of a simplified Kerberos login. Every message after the first is encrypted with a key the attacker never sees in the clear.

Press "Next step" to begin the Alice → AS → TGS → Bob exchange.

PKI & chain of trust — quick check

A certificate is a public key, signed by someone you already trust — chained back to a root CA you trust by default.

🎯 Assessed challenge · 10 marks ⏱ Estimated time: ~15 min

Kerberos & PKI check

Week 7 Secure Communication Protocols

Module 7 — Wrapping traffic: IPsec, TLS, SSH

Same underlying crypto toolkit from Weeks 3–4, wired into real network protocols at different layers.

TLS handshake — step through it

Click through the stages a browser and server go through before the padlock appears.

Press "Next step" to begin the TLS handshake.

Watch a man-in-the-middle attack — then watch TLS stop it

Alice needs to send Bob a funds-transfer instruction. Mallory has positioned herself on the path between them — a rogue Wi-Fi access point, or ARP/DNS spoofing on the local network — so every packet passes through her first. Step through what happens on a plaintext channel, then switch to an encrypted + signed channel (what TLS actually gives you) and watch the same attack fail.

Alice
Mallory (attacker)
Bob
Click Play, or step through with Step ▸, to run the scenario.

Now you try — be Mallory

Below is the plaintext packet Alice is about to send. Edit it the way an attacker would, then send it on to Bob and see what happens — with and without a protected channel.

Alice
You (Mallory)
Bob

IPsec AH vs ESP, and SSH — quick check

🎯 Assessed challenge · 10 marks ⏱ Estimated time: ~20 min

Secure protocols check

Week 8 Email, App-Layer & Firewalls

Module 8 — Securing the edge: email, applications, and the perimeter

PGP reuses Week 4's signatures and encryption directly; firewalls decide what's even allowed to reach your application in the first place.

Firewall rule tester

A simple ordered ACL. Rules are checked top to bottom; the first match wins. Try a few source/destination/port combinations.

#ActionSourceDest port
Enter a source IP and port, then press the button.

Phishing — see it happen, then take it apart

You're a student checking your inbox. One of these messages is a phishing attempt built to look like it's from IT Support. Open it, follow it through the way a busy, trusting user would, and watch what an attacker sees the moment credentials are typed — then pull the email apart and find every red flag. Simulation only — nothing typed here is sent anywhere.

SIMULATION — everything below runs entirely in this page. No email is sent. Nothing typed is transmitted anywhere.
Inbox3 messages
IT Support <it-support@africau-portal-verify.com>
Urgent: Your student portal access will be suspended
Dear Student, we detected unusual activity on your account. Verify now to avoid suspension…
CEAS Weekly <ceas-news@africau.edu>
This week in the College of Engineering
Guest lecture on Friday, library hours extended for finals week…
Tendai M. <tendai.m@africau.edu>
Study group — Thursday 5pm
Same room as last week, bring your notes from Module 4…

Now you build the pretext

Write your own phishing email below. We won't score how "good" it is — instead we'll flag which real-world defenses (spam filters, SPF/DKIM, user training) would likely catch each technique used. That's the more useful lesson: knowing what gets caught, and why.

PGP, OWASP Top 10 & DMZ — quick check

🎯 Assessed challenge · 10 marks ⏱ Estimated time: ~20 min

Email/app security & firewalls check

Week 9 Intrusion Detection & Monitoring

Module 9 — Watching the network: IDS, IPS & SIEM

Detection is a different discipline from prevention — and knowing which detection method is watching changes what it will, and won't, catch.

Alert triage — signature or anomaly?

For each log line, decide whether a signature-based IDS (matches known attack patterns) or an anomaly-based IDS (flags deviation from a learned baseline) is the one that would catch it — or both, or neither.

NIDS vs HIDS, IDS vs IPS, SIEM — quick check

🎯 Assessed challenge · 10 marks ⏱ Estimated time: ~15 min

Detection & monitoring check

Week 10 Risk, Vulnerability Assessment & Review

Module 10 — Risk, assessment, and the whole course at once

Risk management ties everything together: every control you've met since Week 1 exists to push risk down. This closing module scores a risk matrix, then finishes with the course-wide capstone scenario your written report is built on.

Risk-matrix calculator

Risk is commonly scored as Likelihood × Impact on a simple 1–5 scale each. This is exactly the kind of prioritisation a vulnerability assessment report hands to management.

Choose likelihood and impact, then press the button.

Vulnerability assessment vs. penetration testing — quick check

Course-wide capstone: Incident at Mutare TechBank

This is the scenario your written report (see the assignment brief) is built on. Read it once straight through, then use the four prompts below to draft your analysis — one prompt per early-semester week's toolkit.

Mutare TechBank runs an online banking portal for retail customers. On a Tuesday morning, the SOC receives three unrelated-looking alerts within twenty minutes: (1) a spike in failed logins from a narrow range of IP addresses, followed by a handful of successful logins from those same addresses using previously unused, oddly consistent passwords; (2) a customer complaint that a funds-transfer confirmation email they never requested arrived, referencing a transfer they didn't make, for an amount their statement doesn't yet show; (3) a junior developer notices that the bank's mobile app is still encrypting locally-cached transaction receipts one fixed-size block at a time with the same key and no chaining — and when they view the encrypted cache file as an image, they can still make out the shape of the receipt template underneath the "encryption."

🎯 Assessed challenge · 10 marks ⏱ Estimated time: ~20 min

Risk scoring & capstone diagnostic check

Your written report (submitted separately, per the assignment brief) is graded by your lecturer — this automatic check covers precise diagnosis only.

Final step

Results & certificate

Your full-syllabus progress, and — once every module is submitted — your certificate of completion.

Complete and submit all ten assessed challenges to unlock your certificate. Progress: 0/10 submitted.

For lecturers & anyone checking a certificate

Verify a certificate

Enter the Student ID and Certificate ID exactly as they appear on a certificate. This looks the record up on the server that issued it — the same check anyone can run from the public verify page linked on the certificate itself, without needing to open this lab.

Enter a Student ID and Certificate ID, then press Check.