Computer Security: Vulnerabilities and Solutions is a document that discusses computer and internet security. It begins with an introduction to hacking, including the different types of hackers like white hat, black hat, and grey hat hackers. It then discusses common vulnerabilities like viruses, worms, Trojan horses, phishing attacks, and denial of service attacks. The document concludes by providing some common solutions for improving security, such as using antivirus software, firewalls, being cautious of unknown links and apps, and educating yourself on computer security best practices.

1. Computer Security
Vulnerabilities and Solutions.
By Roshan Kumar Bhattarai

2. Table of contents:
• Introduction
• Understanding Hacking.
• Types of Hackers.
• Vulnerabilities: Viruses and other threats.
• Solutions for day-to-day life.
• Conclusions.

3. Introduction to Internet
• What is Internet?
• The Internet is the global system of interconnected
computer networks that use the Internet protocol suite
(TCP/IP) to link billions of devices worldwide.
• It is a network of networks that consists of millions of
private, public, academic, business, and government
networks of local to global scope, linked by a broad array of
electronic, wireless, and optical networking technologies.
• The Internet carries an extensive range of information
resources and services, such as mobile apps including social
media apps, the inter-linked hypertext documents
and applications of the World Wide Web (WWW), electronic
mail, multiplayer online games, telephony, and peer-to-
peer networks for file sharing.

4. Hackers, Crackers and Ethical Hackers
 What is Hacking?
The act of accessing systems without authorization is hacking. In other words breaching
into others’ system without having the required credentials. Hacking is about entering a
system without Username and Passwords.
• Hacker is the person who is involved in the act of hacking.
What is cracking?
The act of destroying a system after hacking is called cracking.
• Cracker is the person who is involved in the act of Cracking.
 What is Ethical Hacking?
The act of hacking a system with prior permission from the owner to check the weakness
of a system is called Ethical Hacking.
Ethical Hacker or Cyber Security Expert is the person who is involved in the act of
Ethical Hacking.

5. Three categories of hackers:
• White hat hackers: A white hat hacker is a computer security specialist who
breaks into protected systems and networks to test and asses their security.
White hat hackers use their skills to improve security by exposing vulnerabilities
before malicious hackers (known as black hat hackers) can detect and exploit
them.
• Black hat hackers: A black hat hacker is an individual with extensive computer
knowledge whose purpose is to breach or bypass internet security. Black hat
hackers are also known as crackers or dark-side hackers.
• Grey hat hackers: The term "grey hat" or "gray hat" in Internet slang refers to a
computer hacker or computer security expert whose ethical standards fall
somewhere between purely altruistic and purely malicious. They are devoted to
help the people but doing wrong things like hacking government websites. They
are concerned about the society.

6. Vulnerabilities:
• What is Computer Virus?
• A computer virus is a program or piece of code
that is loaded onto your computer without your
knowledge and runs against your
wishes. Viruses can also replicate themselves.
• A computer virus might corrupt or delete data
on your computer, use your email program
to spread itself to other computers, or even
erase everything on your hard disk. Computer
viruses are often spread by attachments in
email messages or instant messaging messages
and spread themselves with the help of flash
drives inserted into the infected computers.

7. Types of Computer Viruses:
• Worms: A computer worm is a
standalone malware computer
program that replicates itself in
order to spread to other
computers.
• Trojan Horse: A Trojan horse, often
shortened to Trojan, is a type of
malware designed to provide
unauthorized, remote access to a
user's computer.

8. Phising Attack
• Phishing is the attempt to acquire
sensitive information such as
usernames, passwords, and credit card
details (and sometimes, indirectly,
money), often for malicious reasons, by
masquerading as a trustworthy entity in
an electronic communication.
• Usually hackers make fake login pages
and send them to the users as links
through email. The credentials are sent
to the attacker when the user tries to
log in to the page.

9. DoS Attacks: Denial Of Service
• In computing, a denial-of-service (DoS) attack is
an attempt to make a machine or network
resource unavailable to its intended users, such as
to temporarily or indefinitely interrupt or suspend
services of a host connected to the Internet.

10. Common Solutions:
• Anti-Viruses: The programs designed to detect and destroy computer viruses.
• Allow firewall to protect your system.
• Do not authorize unknown apps in social media.
• Do not open social media/banking sites from external links. Always type the
address in the browser.
• Scan flash devices using anti-virus.
• Do not disclose your personal information to strangers in social media.
• Do not connect to unknown Wi-Fi and other networks. When not in use turn off
Bluetooth and Wi-Fi adapter.
• Before you download any apps make sure it has the encryptions which will
protect your privacy.
• Learn more about Computer and internet security it is no more limited to techies.

11. Demonstrations

12. Thank you!
Login to www.roshankumarbhattarai.com for any help.