Computer Management Grade 11
Safeguarding a computer system requires understanding threats, knowing how malware works, and applying the right remedies.
Keeping a computer safe is like protecting a house. The threats are burglars, fires and floods (malware, hackers, power surges, spills). The remedies are your security measures: a firewall is the perimeter wall and gate, antivirus is the alarm and guard dog, passwords and access rights are the locks on each door, a UPS is a generator for when the power fails, and a backup is a copy of your valuables kept safely off-site. No single measure is enough on its own — you layer them.
Human Error Threats
- Sharing sensitive information with wrong people
- Writing down or reusing passwords
- Clicking links without verifying them
- Leaving devices unlocked / unattended
- Accidentally deleting valuable data
- Entering incorrect data — GIGO ("Garbage In, Garbage Out"): if the input is wrong, the output will be wrong too
Physical Threats
- Theft of devices or storage media
- Hard drive mechanical failure (moving parts)
- Power surges or outages damaging hardware
- Water/liquid spills causing short circuits
Malware
| Type | Description |
|---|---|
| Virus | Attaches to files; replicates when file is run; causes damage |
| Worm | Spreads across networks without user action |
| Trojan | Disguised as useful software; gives attacker back-door access |
| Rootkit | Hides in OS; gives remote attacker control; avoids detection |
| Ransomware | Encrypts data; demands payment to restore access |
| Spyware | Secretly monitors activity and steals data |
| Adware | Displays unwanted pop-up advertisements |
Network Vulnerabilities
| Attack | Description |
|---|---|
| Phishing | Fake official-looking emails to steal credentials |
| Pharming | Redirects users to fake websites |
| Spoofing | Forges sender addresses to impersonate someone |
| SQL Injection | Malicious SQL commands entered via web forms |
Remedies and Protection
| Remedy | Purpose |
|---|---|
| Antivirus | Detects, removes and prevents malware infections |
| Firewall | Filters all incoming and outgoing network traffic |
| Strong passwords | 8+ chars; mix of uppercase, lowercase, numbers, symbols; unique per site |
| User access rights | Users only access files they are authorised for |
| Encryption | Scrambles data so it cannot be read if intercepted |
| UPS | Keeps computer running during power failure |
| Software updates | Patches fix known security vulnerabilities |
| 2FA / MFA | Requires additional verification beyond just a password |
Reasons for Data Loss
Data loss occurs when files become unavailable, corrupted or destroyed. Knowing why data is lost helps you choose the right safeguard for each cause.
| Cause | Example | Safeguard |
|---|---|---|
| Human error | Deleting, overwriting or formatting the wrong files | Backups; access rights; confirmation prompts |
| Hardware failure | Hard-drive crash, worn-out or faulty storage | Backups; replace ageing drives |
| Power problems | Surges or sudden outages corrupt open files | UPS; surge protector |
| Malware | Viruses and ransomware delete, corrupt or encrypt data | Antivirus; updates; offline backups |
| Theft | Stolen laptop, phone or storage media | Encryption; off-site/cloud backup |
| Natural disaster | Fire, flood or lightning destroys equipment | Off-site / cloud backup |
| File corruption | Crashes or bad sectors leave files unreadable | Disk Check; backups |
The single most effective protection against all these causes is a regular, off-site backup — see below.
Backups
| Type | Description | Restore speed |
|---|---|---|
| Full backup | Copy all files every time | Fastest |
| Incremental | Only files changed since last backup (any type) | Slowest to restore |
| Differential | Files changed since last full backup | Moderate |
Backup Locations
- Local — external HDD at same location (fast, but vulnerable to fire/theft)
- Off-site — physical device at another location (protects against local disaster)
- Cloud — Google Drive, OneDrive (automatic, accessible anywhere)
3 copies, on 2 different media types, 1 stored off-site or in the cloud.