Know and understand the use of anti-malware and anti-virus software
4 Networks and the Effects of Using Them
Objective – Know and understand the use of anti‑malware and anti‑virus software
4.1 What is a Network? – Hardware, Basic Concepts and Topologies
A network is a group of computers and other devices that are linked together so they can share resources such as files, printers, internet access and applications.
Key Hardware Components
Device
Primary Role
Security Relevance (Malware Spread)
Network Interface Card (NIC)
Provides the physical (wired) or wireless link between a computer and the network.
Compromised NIC firmware can act as a stealthy entry point for malware.
Router
Routes traffic between different networks (e.g., home LAN ↔ Internet). Provides NAT, DHCP and often a basic firewall.
Routers can be targeted by malware that intercepts or redirects traffic (e.g., DNS hijacking).
Switch
Connects multiple devices within the same LAN and forwards frames only to the intended recipient.
Exploitable for ARP spoofing or VLAN hopping, allowing malware to move laterally.
Hub
Repeats incoming signals to all ports; simple but inefficient.
Because all traffic is broadcast, a compromised device can easily sniff data.
Bridge
Links two separate network segments, making them act as a single network.
Improperly secured bridges can let malware cross from one segment to another.
Common Network Topologies (Cambridge Syllabus)
Topology
Shape / Layout
Typical Use
Security Considerations
Star
All devices connect to a central switch or hub.
Most modern LANs and Wi‑Fi access points.
Failure of the central device disables the whole network; central point must be secured.
Bus
Devices share a single communication line.
Older Ethernet installations.
Easy for a compromised node to sniff all traffic.
Mesh
Each device can connect to multiple others.
Wireless mesh Wi‑Fi, some WAN links.
Provides redundancy but increases attack surface; strong authentication required.
Wireless Technologies
Wi‑Fi (IEEE 802.11) – convenient for laptops, tablets and smartphones but vulnerable to eavesdropping, rogue access points and malware that spreads via shared wireless resources.
Bluetooth – short‑range link for peripherals; can be exploited by malware such as BlueBorne to spread between nearby devices.
Network Types (Syllabus Terminology)
LAN (Local Area Network) – limited to a single building or campus.
WLAN (Wireless LAN) – LAN that uses Wi‑Fi.
WAN (Wide Area Network) – connects LANs over larger distances (e.g., the Internet).
Intranet – private network used within an organisation.
Extranet – part of an intranet that is accessible to selected external users (e.g., partners).
Internet – global public network.
Cloud Computing (Advantages & Disadvantages)
Many schools and businesses store files or run applications in the cloud (Google Drive, Microsoft OneDrive, AWS, etc.).
Advantages
Disadvantages
On‑demand access from any device with internet. Scalable storage and processing power. Automatic backup options.
Dependence on internet connectivity. Potential data‑privacy issues if the provider is compromised. Shared‑resource attacks (e.g., cross‑tenant malware).
Modern anti‑malware suites often include cloud‑based scanning to check files against a constantly updated online threat database, improving detection of new malware.
4.2 Network Issues – Security, Passwords, Anti‑malware, Electronic Conferencing and Data Protection
Security Issues Covered by the Syllabus
Data transfer – files sent by email, USB drives, network folders or cloud services can carry malware.
Passwords & authentication – weak or reused passwords, lack of multi‑factor authentication (MFA) make it easier for attackers to install malware.
Anti‑malware / anti‑virus – essential tools for detecting, quarantining and removing malicious code.
Electronic conferencing – video‑/audio‑calling platforms (Zoom, Microsoft Teams, Google Meet) can be used to deliver malicious links or files.
Privacy & confidentiality – personal and sensitive data must be protected during transfer and storage (GDPR, UK Data Protection Act 2018).
When personal data (name, address, pupil records, etc.) is transferred or stored, the following principles apply:
Lawful, fair and transparent processing – only collect data that is necessary and inform the owner how it will be used.
Purpose limitation – use data only for the reason it was collected.
Data minimisation – keep only the amount of data required.
Security – encrypt files, use strong passwords, and protect devices with anti‑malware.
Accountability – maintain records of who accessed the data and when.
e‑Safety also covers responsible online behaviour, avoiding cyber‑bullying, and reporting suspicious activity.
4.3 What Is Malware?
Malware – any software deliberately created to damage, disrupt or gain unauthorised access to a computer system.
Common types (as listed in the syllabus):
Virus – attaches to legitimate files and spreads when the host file is executed.
Worm – self‑replicates across a network without user interaction.
Trojan horse – appears legitimate but hides malicious code.
Spyware – secretly gathers information about the user.
Adware – displays unwanted advertisements, often bundled with other software.
Ransomware – encrypts data and demands payment for the decryption key (e.g., WannaCry).
Rootkit – hides the presence of other malware and gives attacker privileged access.
Typical threat vectors (expanded to match syllabus wording):
Phishing – deceptive emails or messages that trick users into revealing credentials or downloading malware.
Smishing – phishing via SMS.
Vishing – phishing via voice calls.
Pharming – manipulation of DNS to redirect users to fake sites.
Card‑fraud – malware that captures payment‑card details.
Hacking – unauthorised exploitation of vulnerabilities to install malware.
4.4 Anti‑malware vs Anti‑virus
Historically “anti‑virus” referred only to software that targeted viruses. Modern security suites are called “anti‑malware” because they protect against a wider range of threats.
Feature
Anti‑virus
Anti‑malware (modern suite)
Primary focus
Viruses and simple worms
All malicious software – viruses, worms, trojans, ransomware, spyware, adware, rootkits, etc.
• Clear => Behavioural monitoring while the file runs →
• Malicious behaviour = > Quarantine/Block → End.
• No malicious behaviour => File allowed to execute → End.
4.9 Data Protection, Privacy and e‑Safety Summary
Effective network security for the IGCSE ICT syllabus combines technical safeguards (anti‑malware, firewalls, secure hardware) with good organisational practice (strong authentication, regular updates, user education, and robust data‑protection policies). By understanding how malware spreads, how anti‑malware detects and removes threats, and how to apply e‑safety principles, students can design and maintain networks that are both functional and secure.
4.10 Summary
Anti‑malware and anti‑virus software are essential components of network security. They protect against a wide range of malicious software, help maintain data integrity, support compliance with data‑protection legislation, and keep network performance stable. When combined with sound hardware knowledge, strong authentication, regular updates, user education, and complementary network‑level measures (firewalls, IDS/IPS, VLANs), they provide a robust defence for any school or small‑business network.
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