1. Malicious Software There are various sources via whom a malicious software can enter a system most common of which is through internet sites not only this but ads on internet and pirated content contain a malware and so also an external drive from an infected system is capable of infecting another computer. Malware is of 3 types 1. Virus – It has the ca pability to corrupt an existing file and also if the corrupt file is shared can infect another system. 2. Worms – When it is introduced in a computer system it tries to multiply itself hence worsening the computer performance. It can also be transferred via external hard drive at the time of file sharing. 3. Trojan – Trojan is a form of software which enter the computer masked under a different software but once installed it make a computer system vulnerable to other form of malware and makes a system an easy target for other such software.

2. What is an Antivirus An Antivirus software is an application software. When installed in an computer system the software has its own dictionary of known malware. Whenever one scans their system using the antivirus, what the software does is, it cross check each and every file on the hard disk for the files in its dictionary if any suspicious behavior is detected the interface notifies the user for the appropriate steps to be taken. However it is very rare that human interaction is necessary because antivirus usually deals with malware on its own.

3. Antivirus and Beyond Antivirus was originally developed to detect and remove computer viruses, hence the name. However, with the proliferation of other kinds of malware, antivirus software started to provide protection from other computer threats. In particular, modern antivirus software can protect from: malicious browser helper objects(BHOs), browser hijackers, ransom- ware, keyloggers, backdoors, root kits, Trojan-horses, worms, malicious LSPs, diallers, fraudtools, adwareand spyware. Some products also include protection from other computer threats, such as infected and malicious URLs, spasms, scams and phishing attacks, online identity (privacy), online banking attacks, social engineering techniques, advanced persistent threat(APT) and attacks.

4. Some popular Antivirus softwares Quickheal Avast Antivirus Norton Kaspersky Antivir McAfee Trendmicro Panda Viper However it not important which antivirus but the one being used must be a legal copy and paid version because an antivirus must update on a daily basis any thing else would not be of any benefit.

5. Thankyou Made by Akshat Khanna B.com (Economics) Semester VI