Computer Viruses

Computer Viruses Presented by : vijitha.k

INTRODUCTION

Virus: definition • a virus is a self replicating program. It may spread between files or disks but the defining character is that it can recreate itself without travelling to new host

Overview • How virus infect computer • Symptoms • Classifying Viruses • Examples • Protection/Prevention • Conclusion

How virus infect computer • virus can run before infect your computer • It can attach themselves to other programs • One infected attachment can copy itself to other files

Virus risks • the internet • document and spreadsheets • programs • email • Floppy disk and cds

Symptoms of Virus Attack • 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

Classifying Virus - Types • Trojan Horse • Back door trojans • Worm • Boot sector virus • Parasitic virus • Macro

Trojan Horse • Covert • Leaks information • Usually does not reproduce

Worms • Spread over network connection • Worms replicate • First worm released on the Internet was called Morris worm, it was released on Nov 2, 1988.

Macro • Specific to certain applications • Comprise a high percentage of the viruses • Usually made in WordBasic and Visual Basic for Applications (VBA) • Microsoft shipped “Concept”, the first macro virus, on a CD ROM called "Windows 95 Software Compatibility Test" in 1995

Protection/Prevention • make users aware of the risk • Install antivirus software and update it regularly • Keep backups of all your data

Sources of viruses • e mail • internet

Anti virus softwares • scanners • Check summers • heuristics

Mobile phones and palmtops • virus spread to mobiles through internet usage • Blue tooth

scanning at the gateway or during data transfer Virus scanning on the mobile device don’t install unexpected aplication reduce downloads precaution

Conclusion..

Questions?

Thank you….

Computer Viruses