Comprehensive Notes Network Security Concepts Class 12

Let’s we start the article Comprehensive Notes Network Security Concepts Class 12. We are going to cover the topics from your syllabus for network security concepts. So let’s start!

Comprehensive Notes Network Security Concepts Class 12

The rapid growth of internet and network brought a concept of network security. This article Comprehensive Notes Network Security Concepts Class 12 will focus on the major areas of these aspects. As we think about the security, in network security means that data security, device security etc.

In the first section of Comprehensive Notes Network Security Concepts Class 12 we will discuss threats and prevention.

The network security concerns – Threats and prevention

Network Security Concepts Class 12
Network Security Concepts Class 12

The network security concerns with following with respect to data and devices:

  1. Protection – Protection of devices and data from misuse
  2. Prevention – Prevent unauthorised users from data and devices access
  3. Exploitation – Exploit any vulnerability
  4. Network Weakness – Network weakness can damage the or harm the data and security


This is a very common security threat. It stands for MALisious softWare. It is developed with an intention to damage, steal, or creating trouble for data access. There are different types of Malware created and impacted huge networks. Every year different types of Malware are being created and being populated which makes financial damages as well as resource damage. The different types of malware are as follows:

  1. Viruses
  2. Worm
  3. Ransomeware
  4. Trojans
  5. Spyware

So lets discuss about them in the next section of Comprehensive Notes Network Security Concepts Class 12.


When you hear this word Virus, it gives you different kind of feelings! Isn’t it? The term has been borrowed from biological science. It is similar to that, but only one difference i.e. these viruses effect on computers. The full form of virus is Vital Information Resources Under Seize.

A virus is malicious software developed to perform some malicious activities and damage the resources of computer systems like memory, data, files, programs, and related information.

Some popular examples of viruses are CryptoLocker, ILOVEYOU, MyDoom, Sasser and Netsky, Slammer, Stuxnet, etc.

Virus - Network Security Concepts Class 12
Virus – Network Security Concepts Class 12

Effects of Viruses

How you that your computer get infected with virus? So here are some effects of viruses:

  1. Creating unnecessary files rapidly
  2. Copying files rapidly
  3. Spreads on contact with other computer systems
  4. Insert code in executable files and damage them
  5. Activates themselves when the infected files opened
  6. Stealing data including sensitive information like username and password
  7. Corrupt files
  8. Sending unwanted messages
  9. Access and control the machine as per code written in that
  10. Delete, rename files


Worm stand for Write Once Read Many. It is a Malware that replicates itself and spread itself to other computers through the network. Some examples are Storm Worm, Sobig, MSBlast, Code Red, Nimda, Morris Worm, etc.


It prevents data access from your computer system and asks to pay money. It can simply block the data access or encrypt data to make it very difficult to access.

In May 2017, a ransomware WannaCry infected almost 200,000 computers across 150 countries. It worked by encrypting data and demanding ransom payments in the Bitcoin cryptocurrency. It literally made its victims “cry” and hence the name.


Comprehensive Notes Network Security Concepts Class 12

It is one of the common Malwares. In ancient time, the Greeks could not defeat the King of Troy with the traditional ware. So they have gifted a mammoth wooden horse with hidden soldiers inside it and defeated the King of Troy. This wooden horse was named as Trojan Horse.

Similarly, Trojan virus gets downloaded and after installation it will work like a virus or worm. It does not replicate itself but gets downloaded with user interaction. For example when you open a file from email with attachment or download a file from internet.


Spam refers to sending an unsolicited message to a large number of people with the intention of marketing, advertising, promoting or fraudulent activity through email. It is also referred to as Junk email.

Right now almost all of the email service providers use spam filters and have one folder in emails called “Spam”. So that such type of email you will not receive as spam.

Use of Cookies

The cookies are computer files which store the information related to the user’s session. The cookies files are created by a website and stored into your computer. Cookies can store login credentials, language preference, search queries, recently viewed web pages, music choice, favourite cuisine, etc.

Cookies help to enhance the user experience with the website and make your browsing more productive and time-saving. There are two types of cookies explained in the textbook.

  1. Session Cookies – It stores the current session data. When you leave the website for any reason it will automatically close your session.
  2. Authentication Cookies – It checks certain data related to the user login such as name, address, contact, dob, and fills up it automatically.

Threats due to cookies

There are single-user cookies and third-party cookies. Some third-party cookies share your data without the consent of the user for advertising or tracking purpose.

Protection using firewall

A firewall is hardware or software that protect a trusted private network from unauthorized access or traffic coming from outside.

The firewall give access or deny he malware or any service. It generates a message to allow or deny the service and add a filter. It is working like as watchman. It monitors and controls the incoming and outcoming traffics. There are two types of firewall:

  1. Network Firewall – It monitors the network traffic
  2. Host-based firewall – It is the firewall placed on computer and monitor the network traffic to an from that computer

So I hope you enjoyed this article. Follow the below given link to access all article for computer science class 12.

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