Unit 12: Understanding The Need of Security Measures

Information security is the practice of protecting computer systems, the data they hold, and the people who use them from harm, theft, and disruption. As organisations and individuals move records, money, and communication online, the value concentrated in digital form makes it a target, and a single breach can expose thousands of records at once. This unit frames security around three assets that later sections keep returning to: users, hardware, and data.

I. Basic Security Concepts

Security rests on protecting the confidentiality, integrity, and availability of information (the "CIA triad"), which every measure in this unit ultimately serves.

• Confidentiality: keeping information visible only to authorised people — e.g. encrypting a password file so a thief who copies it cannot read it.
• Integrity: ensuring data is not altered without authorisation — e.g. a checksum that flags a file changed by a virus.
• Availability: ensuring systems and data are usable when needed — e.g. a backup that restores service after a disk failure.
• Threat: any circumstance with potential to cause harm (a hacker, a power surge, a flood).
• Vulnerability: a weakness a threat can exploit (an unpatched operating system, a weak password).
• Countermeasure: a control that reduces risk (antivirus software, a firewall, a locked server room).
• Authentication vs authorisation: authentication proves who you are (password, fingerprint); authorisation decides what you may do once identified.

II. Threats to Users

The people using a system are attacked directly, usually to steal their identity or manipulate their behaviour.

A. Identity theft

• Definition: an attacker impersonates a victim using stolen personal data (name, ID number, card details) to commit fraud.
• Method: harvested data is used to open accounts or make purchases in the victim's name.

B. Loss of privacy and tracking

• Data profiling: websites and advertisers build behavioural profiles from browsing history and purchases without clear consent.
• Surveillance: keyloggers or hidden monitoring software record everything a user types, capturing passwords and messages.

C. Online spam and harassment

• Spam: unsolicited bulk email that wastes time and often carries malicious links.
• Phishing: fraudulent messages disguised as trusted institutions (e.g. a fake "bank" email) that trick users into revealing credentials.
• Cyberbullying: repeated harassment through messages, posts, or impersonation, causing psychological harm.

III. Threats to Hardware

Physical devices are vulnerable to damage, environmental hazards, and theft, any of which can destroy both equipment and the data on it.

A. Power-related threats

• Power failure: a sudden outage causes unsaved work to be lost and can corrupt open files; a UPS (uninterruptible power supply) guards against this.
• Power surge/spike: a voltage jump (from lightning or grid faults) can burn out components; a surge protector diverts excess voltage.

B. Theft and vandalism

• Device theft: laptops and phones are stolen for resale and for the data inside them — often more valuable than the hardware.
• Vandalism: deliberate physical damage to equipment, whether by insiders or intruders.

C. Environmental hazards

• Heat and humidity: overheating warps components and shortens lifespan; server rooms use air conditioning to hold stable temperature.
• Dust, water, and fire: contaminants and disasters cause short circuits and permanent loss; fire suppression and clean environments reduce risk.

IV. Threat to Data

Data is the highest-value asset because it can be copied, altered, or destroyed silently, often without immediate signs.

A. Malware

Malware is software written to damage or gain unauthorised access to a system.

• Virus: attaches to a host file and spreads when that file runs.
• Worm: self-replicating code that spreads across networks without a host file.
• Trojan horse: disguises itself as legitimate software while carrying a hidden harmful payload.
• Ransomware: encrypts a victim's data and demands payment for the key.

B. Unauthorised access and hacking

• Hacking: breaking into a system by exploiting vulnerabilities to steal, alter, or delete data.
• Cracking: defeating passwords or software protection by guessing or brute-force tools.

C. Data loss and corruption

• Accidental loss: human error such as deleting the wrong file or overwriting a record.
• Corruption: partial damage from failing hardware or an interrupted write that leaves a file unreadable.

V. Cyber Terrorism

Cyber terrorism is the use of computer networks to launch attacks intended to cause serious harm, fear, or disruption for political or ideological aims.

• Targets: critical infrastructure such as power grids, banking systems, transport control, and government networks.
• Denial-of-service (DoS): flooding a server with traffic until it collapses, denying service to legitimate users; a distributed attack (DDoS) uses many hijacked machines at once.
• Data destruction and defacement: wiping records or altering websites to spread propaganda.
• Distinction from ordinary crime: motive is disruption and intimidation on a large scale rather than direct personal profit.
• Consequence: because infrastructure is interlinked, one successful attack can cascade — a grid outage can disable hospitals, communication, and finance simultaneously.

VI. Taking Protective Measures

Protection is layered: secure the machine, the person, the privacy, and the data, so that a single failure does not expose everything.

A. Keeping your System Safe

• Antivirus/anti-malware: software that scans for and removes malicious code; must be updated so it recognises new threats.
• Firewall: filters incoming and outgoing network traffic against a rule set, blocking unauthorised connections.
• Patching: applying operating-system and application updates promptly closes known vulnerabilities before attackers exploit them.
• Least privilege: running as a standard user rather than administrator limits the damage malware can do.

B. Protecting Yourself

• Strong passwords: long, mixed-character passwords resist guessing; a unique password per account prevents one breach spreading.
• Two-factor authentication: a second proof (a code sent to a phone) blocks access even if a password leaks.
• Caution with links and attachments: verifying the sender before clicking defeats most phishing.
• Limit shared information: posting less personal detail online reduces material available for identity theft.

C. Protecting your Privacy

• Encryption: scrambling data so only holders of the key can read it, protecting information in transit and at rest.
• Secure connections: using HTTPS and avoiding sensitive transactions on open public Wi-Fi.
• Privacy settings: restricting who can see profiles and posts on social platforms.

D. Managing Cookies

Cookies are small text files a website stores in the browser to remember the user.

• First-party cookies: set by the site being visited, useful for logins and shopping carts.
• Third-party cookies: set by advertisers embedded in a page, used to track browsing across many sites.
• Control: browsers let users view, block, or delete cookies; clearing them and blocking third-party cookies limits tracking while keeping needed sessions working.

E. Spyware and other BUGS

• Spyware: software that secretly collects information about a user and sends it to a third party.
• Adware: displays unwanted ads and often bundles tracking.
• Keyloggers: record keystrokes to capture passwords and messages.
• Defence: anti-spyware scanners, avoiding software from untrusted sources, and reading install prompts to reject bundled extras.

F. Keeping your data secure

• Access control: file permissions and user accounts ensure only authorised people can open or change data.
• Encryption of storage: encrypting drives protects data if a device is stolen.
• Secure deletion: overwriting files (not just deleting) prevents recovery of sensitive data from discarded media.

G. Backing Up data

Backups are copies kept so data survives loss, corruption, or ransomware.

• The 3-2-1 rule: keep 3 copies, on 2 different media, with 1 stored off-site.
• Backup types:
  • Full backup: copies everything; simplest to restore but slow and large.
  • Incremental backup: copies only what changed since the last backup; fast but restore needs the full plus each increment.
• Testing: a backup is only useful if restoration is verified; regular test restores confirm the copy is readable.

H. Safeguarding your hardware

• Physical access control: locked rooms, cable locks, and restricted entry stop theft and tampering.
• Environmental controls: stable temperature, humidity control, and dust-free conditions extend equipment life.
• Power protection: surge protectors and a UPS shield against outages and voltage spikes, giving time to shut down safely.
• Safe handling and disposal: careful transport of portable devices and secure wiping before disposal protect both the hardware and the data it once held.