A firewall, while essential for network security, has limitations in preventing phishing attacks. Firewalls are designed to block unauthorized access to or from a private network, controlling traffic based on predetermined security rules. They are effective in preventing unauthorized intrusions and can help block malware and certain types of hacker attacks. However, phishing attacks often involve deceiving individuals into voluntarily providing sensitive information or clicking on malicious links, usually through emails or deceptive websites. Since this does not necessarily involve unauthorized network access, firewalls cannot always detect or prevent phishing attempts. The best defense against phishing is user education and awareness. Users should be trained to recognize phishing attempts, such as suspicious email addresses, urgent or threatening language, and requests for personal information. Email filters and security software that can detect phishing attempts are also valuable tools in combating these types of attacks.

Signs of spyware infection in a computer system include a noticeable slowdown in system performance, unexpected advertisements or pop-up windows, changes in browser settings or homepage without user input, unusual activity on the task manager or network traffic monitors, and unauthorised changes to system files or settings. Spyware operates covertly, often making its detection challenging. To prevent spyware infections, it is crucial to have up-to-date antivirus software, which can detect and remove spyware. Users should avoid clicking on suspicious links or downloading software from untrusted sources. Keeping software and operating systems updated is vital, as updates often include security patches. Regularly changing passwords and using firewalls can also help prevent unauthorised access. Educating users about the risks of spyware and safe internet practices is equally important in mitigating these risks.

Social engineering in network security involves manipulating individuals into divulging confidential information or performing actions that compromise security. Unlike traditional cyberattacks that target system vulnerabilities, social engineering exploits human psychology. Common tactics include pretexting, where attackers create a fabricated scenario to obtain information; baiting, offering something enticing to lure victims into a trap; and tailgating, where unauthorized persons physically follow authorized persons into restricted areas. To protect against social engineering, individuals should be wary of unsolicited requests for sensitive information, verify the identity of anyone requesting access or information, and be cautious of offers that seem too good to be true. Regular security awareness training can help individuals recognise and respond appropriately to social engineering tactics. Additionally, implementing strict security protocols, such as requiring identification and limiting access to sensitive areas, can reduce the risk of such attacks.

Botnets, networks of infected computers controlled by cybercriminals, are a significant threat in network security. A botnet is created when malware infects a series of computers, allowing the attacker to control them remotely. These infected computers, known as 'bots', can be used to perform mass-scale malicious activities without the knowledge of their owners. Common uses of botnets include launching Distributed Denial of Service (DDoS) attacks, where many infected computers overwhelm a target server with traffic, leading to service disruption. Botnets are also used for spamming, cryptocurrency mining, and distributing more malware. Their danger lies in their scale and ability to leverage multiple infected systems, making them hard to trace and shut down. The vast number of compromised devices can lead to significant damage and disruption, and the decentralised nature of these networks makes defending against them challenging.

A virus is a type of malware that requires human action to replicate and spread, typically attaching itself to a legitimate file or program. Once a user executes the infected file, the virus activates, potentially causing damage to the system, corrupting files, or stealing information. Viruses often spread through email attachments, downloads, or shared drives. In contrast, a worm is a standalone malware that replicates itself to spread to other computers, not needing human intervention or a host program. It exploits vulnerabilities in network security to propagate, often causing widespread damage due to its self-replicating nature. Worms can consume significant system resources, slowing down or crashing systems and networks. They can also carry payloads like spyware or viruses, increasing their potential for harm.