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Unit 1: Security Concepts
ICDL Cat.1 · Data Threats (1.1), Value of Info (1.2), Personal Security (1.3), File Security (1.4)
1.1 Data vs Information & Threats 1.1
Data = raw facts without context (42, Ahmed, 15/03). Information = data processed into meaning (Ahmed scored 42 on March 15). Cybercrime = criminal activity using computers. Hacking = unauthorised access to systems.
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Malicious People
Hackers, cybercriminals who steal data, install malware, or damage systems intentionally.
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Accidents
Deleting files by mistake, clicking phishing links, losing USB drives, spilling liquids on laptops.
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Service Providers
Companies handling your data could have breaches, sell data, or go bankrupt losing your files.
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Disasters
Fire, floods, earthquakes, war can destroy hardware. Backups in different locations are essential!
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Cloud Risks
Loss of data control, privacy concerns, internet dependency when using cloud storage.
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1.2 CIA Triad & Data Protection 1.2
🔒 Confidentiality — only authorised people see data
✅ Integrity — data is accurate and untampered
🔄 Availability — data accessible when needed
✅ Integrity — data is accurate and untampered
🔄 Availability — data accessible when needed
Protect personal info to avoid identity theft and fraud. Protect workplace info to prevent theft, sabotage, accidental loss.
Data protection principles: Transparency, Legitimate purposes, Proportionality. Data subjects = people whose data is collected. Data controllers = organisations managing the data.
1.3 Social Engineering & Identity Theft 1.3
Social engineering = tricking humans (not computers) into revealing confidential info.
| Attack | Method |
|---|---|
| 📞 Vishing | Fake phone calls pretending to be tech support or a bank |
| 📧 Phishing | Fake emails from "trusted" organisations asking for info |
| 👀 Shoulder surfing | Looking over your shoulder to see passwords or PINs |
| 🗑️ Information diving | Searching rubbish for personal documents |
| 💳 Skimming | Hidden device on ATMs that copies card data |
| 🎭 Pretexting | Inventing a fake scenario to trick you into sharing info |
1.4 File Security: Encryption & Passwords 1.4
| Feature | What It Does |
|---|---|
| 🔐 Encryption | Scrambles data — only someone with the key can read it. Lose the key = lose data forever! |
| ⚠️ Macro security | Macros in documents can be malicious. Keep macro security HIGH! |
| 🔑 File passwords | Protect documents, spreadsheets, and ZIP files with passwords |
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Quiz: Security Concepts
8 questions
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Unit 2: Malware
ICDL Cat.2 · Types (2.1), Protection (2.2), Removal (2.3)
2.1 Malware Types 2.1
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Virus
Attaches to files, spreads when shared. Needs human action (opening a file). Corrupts/deletes data.
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Worm
Spreads automatically over networks WITHOUT user action. Self-replicates, slows everything down.
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Trojan
Disguised as legit software (free game, tool). Once installed, gives attackers secret access.
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Ransomware
Encrypts ALL your files, demands payment. Never pay — no guarantee of recovery!
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Spyware
Secretly monitors your activity — tracks browsing, captures passwords. Silent and hidden.
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Adware
Floods you with unwanted ads — pop-ups, banners, redirects. Slows your computer.
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Keylogger
Records every keystroke — passwords, messages, credit cards. Works silently.
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Botnet
Your device becomes a "zombie" controlled remotely. Used for spam or DDoS attacks.
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Rootkit/Backdoor
Hides deep in your system giving attackers ongoing secret access. Very hard to detect.
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2.2 Protection 2.2
| Action | Why |
|---|---|
| 🛡️ Install anti-virus (ClamAV = free!) | Scans and blocks malware |
| 🔄 Update ALL software regularly | Patches security holes in OS, browser, apps |
| 🚫 Never open unknown attachments/links | Most malware arrives via email or downloads |
| 📅 Schedule automatic scans | Regular scanning catches threats early |
| ⚠️ Avoid obsolete software | No security updates = big vulnerability |
2.3 Quarantine & Removal 2.3
Quarantine = isolating infected files in a safe area where they can't harm anything. Then delete or restore if false alarm. Use anti-virus provider websites and OS support sites for help with infections.
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Quiz: Malware
8 questions
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Unit 3: Network Security
ICDL Cat.3 · Networks (3.1) & Wireless (3.2)
3.1 Network Types & Firewalls 3.1
| Type | What |
|---|---|
| LAN | Local network — one building |
| WLAN | Wireless LAN (WiFi) |
| WAN | Wide area — cities/countries (Internet) |
| VPN | Encrypted private tunnel over the internet |
Network risks: malware spread, unauthorised access, privacy loss. Network admins manage authentication, install patches, monitor traffic, handle malware.
Firewall = security guard monitoring incoming/outgoing traffic, blocking suspicious connections. On Linux:
ufw (Uncomplicated Firewall). Limitation: can't scan encrypted traffic or stop you clicking phishing links!3.2 Wireless Security 3.2
| Protocol | Security |
|---|---|
| WEP | ❌ Weak — don't use! |
| WPA | ⚠️ Outdated |
| WPA2/WPA3 | ✅ Strong — always use this! |
| MAC Filtering | Only allows specific devices |
| SSID Hiding | Hides network name |
⚠️ Open WiFi dangers: Eavesdropping, network hijacking, man-in-the-middle attacks. Never enter passwords/banking on open WiFi!
Personal hotspot: Turns your phone into a WiFi router using mobile data. Always set a strong password, disable when not in use.
📖 References
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Quiz: Network Security
8 questions
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Unit 4: Access Control & Passwords
ICDL Cat.4 · Methods (4.1) & Password Management (4.2)
4.1 Access Control Methods 4.1
| Method | What |
|---|---|
| 👤 Username + Password | You identify (username) and prove (password) |
| 🔢 PIN | Short numeric code |
| 🔐 Encryption | Scrambles data |
| 📱 Multi-factor (MFA) | 2+ methods: know (password) + have (phone) + are (fingerprint) |
| 🔑 One-time password (OTP) | Single-use code sent to phone/email |
4.1.5 Biometric Security 4.1.5
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Fingerprint
Scans your unique fingerprint. Used on phones, laptops, door locks. Fast and convenient.
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Eye Scan
Iris or retina scan — unique eye pattern. Very accurate. High-security facilities.
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Face Recognition
Camera identifies your face. Unlocks phones, airport security.
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Hand Geometry
Measures hand shape and size. Workplace access control.
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4.2 Password Best Practices 4.2
✅ At least 12 characters
✅ Mix uppercase + lowercase + numbers + symbols
✅ Different password per service
✅ Change every 3–6 months
✅ Never share
❌ Never: your name, birthday, "password", "123456"
✅ Mix uppercase + lowercase + numbers + symbols
✅ Different password per service
✅ Change every 3–6 months
✅ Never share
❌ Never: your name, birthday, "password", "123456"
Password managers (KeePassXC — open-source!) store all passwords under one master password. Lock/log off accounts when not in use.
🎮 Test Password Strength
💡 This is just practice — never type real passwords into untrusted forms!
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Quiz: Access Control
8 questions
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Unit 5: Secure Web Use
ICDL Cat.5 · Browser Settings (5.1) & Secure Browsing (5.2)
5.1 Browser Privacy 5.1
| Setting | Action |
|---|---|
| Autocomplete/Autosave | Disable on shared computers! |
| Browsing history | Clear regularly |
| Cache & Cookies | Clear periodically (Ctrl+Shift+Delete in Firefox) |
| Saved passwords | Use a password manager instead |
5.2 Secure Browsing 5.2
🔒 Always check for https:// and the padlock icon. NEVER enter passwords or payment info on http:// sites!
Verify websites by: Content quality (no errors), valid URL (correct domain, not g00gle.com), company info, contact details, security certificate (click padlock).
Pharming = redirects you to a fake site even when you type the correct URL (DNS hijacking).
Content-control: Internet filtering software blocks harmful sites. Parental controls limit children's access.
📖 References
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Quiz: Secure Web
8 questions
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Unit 6: Communication Security
ICDL Cat.6 · Email (6.1), Social Networks (6.2), VoIP/IM (6.3), Mobile (6.4)
6.1 Email Security 6.1
Email encryption scrambles messages. Digital signature proves sender identity. Phishing uses fake logos, false links, urgency, requests for personal info.
🚫 Never open attachments from unknown senders, especially macros (.docm) or executables (.exe)!
🎮 Spot the Phish!
Is each email SAFE or PHISHING?
6.2 Social Network Safety 6.2
| Danger | What |
|---|---|
| 🔓 Privacy leaks | Sharing too much personal info publicly |
| 😢 Cyberbullying | Online harassment and cruelty |
| 🎭 Fake identities | People pretending to be someone else |
| 🔗 Malicious links | Links leading to malware or scams |
Review privacy settings regularly. Report inappropriate behaviour to the platform and authorities.
6.3 VoIP & Messaging 6.3
Vulnerabilities: malware via file sharing, backdoor access, eavesdropping. Use encryption, avoid sharing sensitive info, restrict file sharing.
6.4 Mobile Security 6.4
| Risk | Protection |
|---|---|
| Unofficial app stores | Only use official stores (F-Droid for open-source!) |
| Excessive app permissions | Review and deny unnecessary permissions |
| Apps extracting private data | Check permissions in Settings |
| Lost/stolen device | Enable remote wipe, disable, locate features |
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Quiz: Communications
8 questions
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Unit 7: Secure Data Management
ICDL Cat.7 · Backup (7.1) & Secure Deletion (7.2)
7.1 Physical Security & Backups 7.1
Don't leave devices unattended. Log equipment. Use cable locks.
Backup = safety net! A copy in a SEPARATE location. If device is lost/stolen/attacked — restore everything!
| Feature | Recommendation |
|---|---|
| Frequency | Daily (important), weekly (general) |
| Schedule | Automatic! |
| Location | Different from original: external drive, cloud (Nextcloud!), network |
| Compression | .zip or .tar.gz to save space |
7.2 Secure Deletion 7.2
Regular delete → Trash (recoverable)
Empty Trash → seems gone but data still on drive (recoverable with tools!)
Permanent deletion → overwrites data, truly unrecoverable
Empty Trash → seems gone but data still on drive (recoverable with tools!)
Permanent deletion → overwrites data, truly unrecoverable
| Method | How |
|---|---|
| 🔨 Physical destruction | Drilling, crushing the drive |
| 📀 Shredding | Industrial shredding machines |
| 🧲 Degaussing | Strong magnets erase magnetic data |
| 💻 Data destruction software | Overwrites multiple times (DBAN — open-source!) |
⚠️ Content on social media, blogs, forums, cloud may NEVER be truly gone — copies may exist. Think before you post!
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Quiz: Data Management
6 questions
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Final Exam: Cyber Security
20 questions · All 7 categories · Score 70%+ to pass!
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