AHMER HASSAN

AHMER HASSAN. WELCOME TO LEARN WITH AHMER. 1.

Computer Virus. 2.

Content. Introduction What is Computer Virus Types of Infection Types of Computer Virus Difference between Virus and Worm Signs of a Computer Virus Preventions Top Seven Antiviral Program Conclusion.

Introduction. A virus is a program designed by a computer programmer ( malicious hacker ) to do a certain unwanted function.

What is computer virus?. Computer virus refers to a program which damages computer systems and/or destroys or erases data files.

VIRUSES. A virus is a small piece of Software that piggybacks on real programs. Two main characteristics of viruses It must execute itself It must replicate itself.

Types of Computer Viruses: E-MAIL VIRUSES. Moves around in e-mail messages It replicate itself by automatically mailing itself to dozens of people in the victim’s email address book Example “MELISSA VIRUS” Example “I LOVE YOU VIRUS”.

Melissa Virus (March 1999). Melissa virus spread in Microsoft Word documents sent via e-mail How it works ? Created the virus as word document Uploaded to an internet newsgroup Anyone who download the document and opened it would trigger the virus Send friendly email messages to first 50 people in person’s address book.

Melissa Virus. Melissa Virus was the fastest spreading virus ever seen Forced a number of large companies to shut down their e-mail systems.

I Love You Virus. Contained a piece of code as an attachment. Double Click on the attachment triggered the code Sent copies of itself to everyone in the victim’s address book Started corrupting files on the victim’s machine.

WORMS. Small piece of software that uses computer networks and security holes to replicate itself Copy of the worm scans the network for another machine that has a specific security hole Copy itself to the new machine using the security hole and start replicating Example “CODE RED”.

TROJAN HORSES. A simple computer program It claim to be a game Erase your hard disk No way to replicate itself.

Types of Computer Virus. Time Bomb A time bomb is a virus program that performs an activity on a particular date Logical Bomb A logical bomb is a destructive program that performs an activity when a certain action has occurred.

Types of Computer Virus. Boot Sector Virus A boot sector virus infects boot sector of computers. During system boot, boot sector virus is loaded into main memory and destroys data stored in hard disk.

Types of Computer Virus. Macros Virus A macro virus is associated with application software like word and excel. When opening the infected document, macro virus is loaded into main memory and destroys the data stored in hard disk.

Difference between Virus and Worm. The difference between a worm and a virus is that a virus does not have a propagation vector. i.e. it will only effect one host and does not propagate to other hosts Worms propagate and infect other computers. Majority of threats are actually worms that propagate to other hosts.

World-wide damage estimates. Computer viruses cause a huge amount of damage worldwide Damages from just one virus (The I Love You Virus) are estimated at $10 billion dollars. It is also estimated that 45 million people worldwide were affected.

Signs of a Computer Virus. Computer runs slower then usual Computer no longer boots up Screen sometimes flicker PC speaker beeps periodically System crashes for no reason Files/directories sometimes disappear Denial of Service ( DoS ).

Prevention. Anti-Viruses Updates More secure operating systems e.g. UNIX.

Top Seven Antiviral Program. Bitdefender Antivirus Norton AntiVirus . Kaspersky Anti - Virus Trend Micro Antivirus Webroot Secure Avast antivirus Sophos Home.

Conclusion. Be aware of the new infections out there. Take precaution measures. Always backup your data. Keep up-to-date on new Anti virus software. Simply avoid programs from unknown sources..

Reference. www.google.com www.wikipedia.com www.studymafia.org.