Network security is concerned with the protection of our devices as well as data from illegitimate access or misuse. A computer with no link to an external device or network is free from security threats, but in a fully connected world, staying aloof is not a practical solution. Threats include all the ways in which an attacker can exploit any vulnerability or weakness in a network or communication system to cause harm or damage reputation.
| Core Computer Science Concept | Technical Definition / Operational State | Structural Parameters & Specifications | Computational Function & System Purpose |
|---|---|---|---|
| Network Security | Protection of devices and data from unauthorized access, modification, or destruction. | Encompasses confidentiality, integrity, and availability (CIA triad) across network nodes. | To mitigate vulnerabilities and prevent unauthorized exploitation of communication systems. |
Malware (Malicious Software) is any software developed with the intention to damage hardware devices, steal data, or cause disruption to the user. Common types include viruses, worms, ransomware, trojans, spyware, adware, and keyloggers.
A computer virus is a piece of software code created to perform malicious activities and hamper system resources (CPU time, memory, files). Coined by Fred Cohen in 1985, it mimics biological viruses by spreading on contact (copying its code into other executable files). It remains dormant until the infected file is executed by a user.
Examples: CryptoLocker , ILOVEYOU , MyDoom , Sasser , Netsky , Slammer , Stuxnet .
A worm is a standalone malware program that replicates on its own and spreads to other computers through the network without needing a host program or human triggering.
Examples: Storm Worm , Sobig , MSBlast , Code Red , Nimda , Morris Worm .
A type of malware that targets user data by blocking access or encrypting files, demanding a ransom payment (often in cryptocurrency like Bitcoin) to restore access.
In May 2017, the WannaCry ransomware infected almost 200,000 computers across 150 countries, demanding ransom payments in Bitcoin.
Socio-Technical Analysis & Core Systemic Impact: WannaCry exploited a vulnerability in the Windows SMB protocol. It demonstrated how critical infrastructure (including hospitals and transport networks) can be paralyzed globally by automated, self-propagating ransomware payloads combined with cryptographic locking mechanisms.
A Trojan is a malware that masquerades as legitimate software. Once installed, it performs malicious actions (like creating backdoors for unauthorized access) but does not self-replicate.
A type of malware that spies on users or organizations by gathering information (internet usage, credit card details, login credentials) without their knowledge or consent and sending it to external entities.
Malware designed to generate revenue for its developer by displaying unwanted online advertisements (pop-ups, web pages) or using "pay per click" mechanisms.
A keylogger (software or hardware) records keystrokes pressed by a user to steal sensitive information like passwords and private conversations.
Online Virtual Keyboard vs. On-Screen Keyboard:
Common signs of infection include frequent pop-ups, changes to browser homepage, mass emails sent without consent, unusually slow performance, and files disappearing.
Preventive measures: regular antivirus updates, configuring browser security, checking for HTTPS lock icons, using FOSS, backing up data, and avoiding suspicious links.
An antivirus (or anti-malware) is software designed to prevent, detect, and remove a wide range of malicious software.
Technical Profile: Antivirus Software
Spam refers to unsolicited, unwanted digital messages (primarily email spam) sent in bulk to advertise, phish, or distribute malware. Modern email services use automatic spam filtering algorithms to detect and isolate these messages.
Both are protocols governing data transmission over the World Wide Web:
A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predefined security rules, acting as a barrier between a trusted internal network and untrusted external networks.
Technical Profile: Firewall
A cookie is a small \text file or data packet stored by a website on the client's computer to track browsing information, maintain sessions, and store user preferences (like shopping carts or login states).
While generally harmless, cookies can be exploited:
Individuals with deep technical knowledge of computer systems, networks, and programming who find loopholes and vulnerabilities.
Security experts who use their skills ethically to find and fix security flaws, helping organizations secure their systems.
Individuals who maliciously and unethically exploit system vulnerabilities to break laws, steal data, or disrupt services.
Neutral hackers who exploit vulnerabilities for fun or challenge without malicious intent or financial gain, often disclosing flaws to owners without authorization.
A Denial of Service (DoS) attack overloads a target resource (like a web server) with illegitimate requests, making it unavailable to legitimate users.
A Distributed Denial of Service (DDoS) attack is a variant where the flooding requests originate from multiple compromised systems ( Zombies ) distributed globally, controlled collectively as a Bot-Net .
Unauthorized activities on a network that threaten security and data integrity:
Snooping (or Sniffing) is the secret capture and analysis of network traffic. Network administrators use it for troubleshooting, but attackers use it to intercept unencrypted data.
Eavesdropping is the unauthorized, real-time interception of private communications (like VoIP calls, video conferences, or instant messages) over a network.
Difference: Eavesdropping occurs in real-time, whereas snooping involves capturing and storing traffic for later analysis.