Cause and effects of computer virus.

Agenda 1.Computer virus

3. Symptoms

4. Risky file type

6. Types Of Viruses

2.History

• A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user.

• A computer virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or the Internet, or by carrying it on a removable medium such as a floppy disk, CD, or USB drive.

History1981 Apple Viruses 1, 2, & 3

1980’s Fred Cohen

1987 Lehigh Virus

1988 The first anti virus software

1990 The first polymorphic viruses

1991 Symantec releases Norton Anti Virus

1992 The Michelangelo Virus

1994 Kaos4 virus spreads via adult websites.

SYMPTOMS

The following are a few Symptoms that your computer might have a virus:• Slow response and slow program execution.• Random hard drive crashes and restarts.• Distorted graphics and text.• Files that have mysteriously vanished.•PC speaker beeps periodically.• Inability to open files with existing passwords.

Examples of risky file typesThe following file types should be treated with suspicion and be confirmed with the sender before being opened:

.exe .pif .bat .vbs .com

Types Of Computer Viruses1. Boot Sector Virus.2. Direct Action Virus.3. File Infector Virus.4. Macro Virus.5. Multipartite Virus.6. Polymorphic Virus.7. Resident Virus.8. Web Scripting Virus.

Boot Sector Virus

It places its own codesand commands into MBR.

Browser HijackerAlters the search and error page of a browser and redirectsthe user to its own page.

Direct Action Virus

•They load with the host program into computer’s memory.

•They can be crafted with relative ease.

File Infector Virus

A file infector is a virus that infects an executable file.

Typically affects only one type of file.

Macro Virus

• These type of virus infects word , excel, PowerPoint, access and other data files. Once infected repairing of these files is very much difficult.

Multipartite Virus

• May attack in more than one methods.

Polymorphic Virus• A virus that can

encrypt its code in different ways so that it appears differently in each infection. These viruses are more difficult to detect.

Resident Virus• Hides within the computers memory.• It activates whenever the OS loads or operates.• This virus may be pernicious.• It is of 2 types: Fast Infector. Slow Infector.• Removal of this virus is bit tricky.• It may be designed to block the actions of Anti

Virus programs.

WEB SCRIPTING VIRUS

There are few website that execute complex code with the purpose to provide interesting content ,these codes often get exploited and due to this a virus becomes able to infect a machine and to take actions on a machine via website. This particular virus is called web scripting virus

LATEST VIRUSES

DEXTER

DEXTERInfects computers running with Microsoft Windows.Discovered by IT security firm Seculert, in December 2012.Steals confidential data of the user.Affects POS i.e. Point of sales.Detected in online banking transaction space on 19 January 2014 in India.

REVETON

REVETONIn 2012, a major ransom ware worm known as Reveton began to spread. A Reveton is a malware which attempts to extort money from a user.It claims that your computer has been used for unauthorized activities.

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