History, Classifications and Structure

PRESENTED BY : IMRAN AHMED KHANUniversity of Texas at Tyler

A computer virus is a computer program that can replicate itself and spread from one computer to another.

A program that alters other programs to include a copy of itself

A computer program able to infect other programs by modifying them to include a

Possibly evolved version of Itself.

Computer virus is a segment of machine code (typically 200-4000 bytes)

Do undesirable things ( damages )

Destructive Software

SearchSearch for the Host program.

CopyCopy itself into the executable program.

Anti-DetectionRoutines to prevent viruses from being detected.

Payload Performs the function(s) for which virus was designed.

Shell virusesA shell virus is one that forms a “shell” around the

original code. In effect, the virus becomes the program, and the original host program becomes an internal subroutine of the viral code.

Add-on virusesThey function by appending their code to the host

code. The add-on virus then alters the startup information of the program, executing the viral code first. The host code is left almost completely untouched

Intrusive virusesIntrusive viruses operate by overwriting some or all

of the original host code with viral code. The replacement might be selective, as in replacing a subroutine with the virus.

As soon as user run the host program which is infected.

Specific date or time. Examining user keystrokes for a specific

sequence. Some random event.

Sample Source Code

Setting up a test machine

Knowledge of all viruses in detail

How it infects executable, what to look for to determine that the executable has been infected.

Knowledge of anti-detection techniques.

First generation: SimpleDo Replication only.Detect easily.Cannot Hide itself. Second generation: Self-recognitionSolved one problem in prior generation viruses.Prevent unnecessary growth of infected files.Use of signature. Third Generation: StealthHide itself from detection.

Fourth Generation: ArmoredAdd confusing and unnecessary code to make it

more difficult to analyze and detect the virus code.

Direct attack against Anti-virus software.

Fifth Generation: PolymorphicSelf mutating viruses.Their modified version or encrypted version.Difficult to identify

These viruses are not limited to computers or laptop only. Virus can attack any hand held device as well.

The more we know about viruses the more we can protect our devices from it.

http://en.wikipedia.org/wiki/Computer_virus

http://www.zdnet.com/blog/bott/the-malware-numbers-game-how-many-viruses-are-out-there/4783

http://www.symantec.com/security_response/definitions/rapidrelease/detail.jsp?relid=2012-09-05

http://www.infinitechusa.net/blog/2012/05/01/number-of-viruses/

http://www.makeuseof.com/tag/history-computer-viruses-worst-today-case-wondering/

http://www.antivirusworld.com/articles/history.php

http://www.ehow.com/info_8706914_three-structural-parts-computer-virus.html

“Computer Viruses as Artificial Life” - Eugene H. Spafford , Department of Computer Sciences

Purdue University