1.4 Network Security

• Network Security

  Any activity designed to protect the usability and integrity of a network and its data by managing access to the network
• Types of Hackers

  • White hat hackers
  • Black hat hackers
  • Hacktivists
  • Ethical hackers
• White hat hackers

  • Hack companies to see how strong their security is
• Black hat hackers

  • Criminals
• Hacktivists

  • Use technology to announce a social, ideological, religious or political message
• Ethical hackers

  • Security specialists hired to find out how secure a network is
• Kiddie script

  Scripts that learn how to hack by themselves to have fun
• Cybersecurity

  The practice of protecting systems, networks, and programs from digital attacks
• Disadvantages of Network Security

  • If one computer is hacked, others can be accessed as they are connected
  • If connected to a network, it can be easily hacked
  • Viruses can spread more easily as everything is connected
  • Networks are more attractive to hackers as there is more data
• Passive attack

  Monitoring data travelling and intercepting sensitive data using software packet sniffers
• Active attack

  Hacking a network/system with malware
• Insider attack

  Someone within an organisation exploits their network access to steal information
• Brute-force attack

  Used to gain information by cracking passwords through trial and error using automated software to produce 100% of possible password combinations
• Denial-of-service attack

  Hacker tries to stop users from accessing a part of a network/website by flooding the targeted machine/website with lots of requests in an attempt to overload the system
• Distributed denial-of-service attack

  Same as a denial-of-service attack but with multiple computers making the attacks at the same time, making it lot harder to stop
• Types of Malware

  • Scareware
  • Ransomware
  • Spyware
  • Rootkits
• Scareware

  Tells the user their computer is infected with lots of viruses to scare them into falling for malicious links or paying for problems to be fixed
• Ransomware

  Encrypts all the files on a computer and the user receives a message demanding money to be paid in exchange for a decryption key
• Spyware

  Secretly monitors actions and sends info to the hacker
• Rootkits

  Alter permissions, giving malware and hackers administrator-level access to a device
• Viruses

  Attach to files and spread by tricking users into activating them by opening infected files
• Worms

  They self-replicate without any user help and can spread very quickly by exploiting weaknesses in network security
• Trojans

  Malware disguised as legitimate software that users install not realising they have a hidden purpose
• Social engineering

  Gaining sensitive information by influencing people
• Phishing

  Criminals send emails/texts to people claiming to be from well-known businesses, with the email containing links to spoof versions of the company's website to request the user to input sensitive information
• SQL injection

  Pieces of SQL code injected into a website's input box to access information in databases
• Network forensics

  • Investigate to find the cause of hacks
• Preventive Measures


  • Network policies
  • Anti-malware software
  • Firewalls
  • User access levels
  • Physical security
• Firewalls

  Examine all data entering and leaving the network and block any potential threats
• Passwords

  Should be strong, long, and a combination of letters, numbers and symbols, changed regularly to prevent unauthorised access
• Encryption

  Data is translated into a code which only someone with the correct key can access
• Two-factor authentication

  Added layer of security to confirm the user's identity by sending a text or email