The document provides an overview of network security, detailing its components such as authentication, firewalls, and vulnerability management. It discusses various forms of malware including viruses, trojans, and worms, explaining their methods of operation and the risks they pose to computer systems. Additionally, it touches on the role of hackers and the significance of the Information Technology Amendment Act of 2008 in India, which updates the regulatory framework for cybersecurity.

1. Network Security And Viruses
Aamlan Saswat Mishra
Class-XI-E

2. Network security
 Network security consists of the policies adopted to prevent and monitor
authorized access, misuse, modification, or denial of a computer network and
network-accessible resources.
 Networks can be private, such as within a company, and others which might be
open to public access. Network security is involved in organizations, enterprises,
and other types of institutions. It does as its title explains: It secures the network,
as well as protecting and overseeing operations being done.
 Network security starts with authenticating, commonly with a username and a
password
 Once authenticated, a firewall enforces access policies such as what services are
allowed to be accessed by the network users
 Communication between two hosts using a network may be encrypted to maintain
privacy
 Security management for networks is different for all kinds of situations.

4. Vulnerability
 The probability that an asset will be unable to resist the actions of a threat agent
 In computer security, a vulnerability is a weakness which allows an attacker to
reduce a system's information assurance. Vulnerability is the intersection of three
elements: a system susceptibility or flaw, attacker access to the flaw, and
attacker capability to exploit the flaw.
 Vulnerability management is the cyclical practice of identifying, classifying,
remediating, and mitigating vulnerabilities. This practice generally refers to
software vulnerabilities in computing systems.
 A security risk may be classified as a vulnerability but there are vulnerabilities
without risk
 Many software tools exist that can aid in the discovery (and sometimes removal) of
vulnerabilities in a computer system. Though these tools can provide an auditor
with a good overview of possible vulnerabilities present, they can not replace
human judgment.

6. A Cookie?

7. HTTP cookie
 An HTTP cookie is a small piece of data sent from a website and stored in the
user's web browser while the user is browsing it
 Every time the user loads the website, the browser sends the cookie back to the
server to notify the user's previous activity. (Cookies were designed to be a
reliable mechanism for websites to remember stateful information)
 Cookies can also store passwords and form content a user has previously entered,
such as a credit card number or an address.
 The tracking cookies, and especially third-party tracking cookies, are commonly
used as ways to compile long-term records of individuals' browsing histories – a
potential privacy concern
 The security of an authentication cookie generally depends on the security of the
issuing website and the user's web browser, and on whether the cookie data is
encrypted. Security vulnerabilities may allow a cookie's data to be read by a
hacker, used to gain access to user data, or used to gain access.

8. Computer virus
 A computer virus is a malware program that, when executed, replicates by
inserting copies of itself (possibly modified) into other computer programs,
data files, or the boot sector of the hard drive; when this replication
succeeds, the affected areas are then said to be "infected“
 Viruses often perform some type of harmful activity on infected hosts, such as
stealing hard disk space or CPU time, accessing private information,
corrupting data, displaying political or humorous messages on the user's
screen, spamming their contacts, logging their keystrokes, or even rendering
the computer useless. However, not all viruses carry a destructive payload or
attempt to hide themselves—the defining characteristic of viruses is that they
are self-replicating computer programs which install themselves without user
consent.
 Virus writers use social engineering and exploit detailed knowledge of
security vulnerabilities to gain access to their hosts' computing resources.

9. And there is more…
 Motives for creating viruses can include seeking profit, desire to send a
political message, personal amusement, to demonstrate that a vulnerability
exists in software, for sabotage and denial of service, or simply because they
wish to explore artificial life and evolutionary algorithms
 Computer viruses currently cause billions of dollars' worth of economic
damage each year, due to causing systems failure, wasting computer
resources, corrupting data, increasing maintenance costs, etc.
 In response an industry of antivirus software has cropped up, selling or freely
distributing virus protection to users of various operating systems.

11. A horse?

12. Trojan horse
 A Trojan horse, or Trojan, in computing is any malicious computer program which
misrepresents itself as useful, routine, or interesting in order to persuade a victim
to install it
 While Trojans and backdoors are not easily detectable by themselves, computers
may appear to run slower due to heavy processor or network usage
 If installed or run with elevated privileges a Trojan will generally have unlimited
access. What it does with this power depends on the motives of the attacker.
 Its target functionalities involve crashing computers, modification or deletion of
files, data corruption, use of resources and identity, money theft, data theft,
spying, survelience and even tracking.
 It is possible for those involved with Trojans to scan computers on a network to
locate any with a Trojan horse installed, which the hacker can then control.

13. Computer worm
 A computer worm is a standalone malware computer program that replicates
itself in order to spread to other computers
 It uses a computer network to spread itself, relying on security failures on the
target computer to access it. Unlike a computer virus, it does not need to
attach itself to an existing program
 Users can minimize the threat posed by worms by keeping their computers'
operating system and other software up-to-date, avoiding opening
unrecognized or unexpected emails, and running firewall and antivirus
software
 Regardless of their payload or their writers' intentions, most security experts
regard all worms as malware.
 Several worms, like XSS worms, have been written to research how worms
spread

14. Spamware
 Spamware is software designed by or for spammers
 Spamware varies widely, but may include the ability to import thousands of
addresses, to generate random addresses, to insert fraudulent headers into
messages and to use dozens or hundreds of mail servers simultaneously
 Being an automated software it can create e-mail broadcasting hub by
establishing superiority in numbers and sending capability as well as brings a
position of great disturbance to its target
 Another type of spamware is software used to search for e-mail addresses to
build lists of e-mail addresses to be used either for spamming directly or to be
sold to spammers

15. And Who Is HE?

16. The hackers
 In the computer security context, a hacker is someone who seeks and exploits weaknesses in
a computer system or computer network.
 Hackers may be motivated by a multitude of reasons, such as profit, protest, challenge,
enjoyment, or to evaluate those weaknesses to assist in removing them.
 The subculture that has evolved around hackers is often referred to as the computer
underground and is now a known community
 The term hacker is reclaimed by computer programmers who argue that someone who breaks
into computers, whether computer criminal (black hats) or computer security expert (white
hats)
 A typical approach in an attack on Internet-connected system is:
 1.Network enumeration: Discovering information about the intended target.
 2.Vulnerability analysis: Identifying potential ways of attack.
 3.Exploitation: Attempting to compromise the system by employing the vulnerabilities found
through the vulnerability analysis

17. Information Technology Amendment
Act 2008
 The Information Technology Amendment Act, 2008 (IT Act 2008) is a
substantial addition to India's Information Technology Act (ITA-2000).
 The original Act was developed to promote the IT industry, regulate e-
commerce, facilitate e-governance and prevent cybercrime
 The Amendment was created to address issues that the original bill failed to
cover and to accommodate further development of IT and related security
concerns since the original law was passed
 Changes in the Amendment include: redefining terms such as "communication
device" to reflect current use; validating electronic signatures and contracts;
making the owner of a given IP address responsible for content accessed or
distributed through it; and making corporations responsible for implementing
effective data security practices and liable for breaches