1. Study of Computer Virus Worms Sampath Yerramalla 04/17/02

2. Survey  Virus Appearance –National Press –Faster than in papers Melissa The Love Letter Anna Kournikova  Vulnerabilities –Computer hardware based on single trusted user –Software loop-holes  Research : Any machine with almost any OS can support virus

3. Difference  Virus –A computer program that replicates by attaching itself to some other object –Usually small size programs ( 3-30k ) –Designed to evade detection  Worm –First reported ed by John Shoh and Jon Hupp of XEROX PARC –Sends itself to other systems –Bigger in size than virus –More abilities –Not easy to write

4. Virus Spread  Medium –Hard disk –Floppy disks –Tape –Optical media –Memory  Internet –E-mail attachments –.exe.bat.vbs  Incentive and trap –Money –Sex –Humor  Research : One in every five hundred e-mail messages contain a virus.

5. Types  Effect on OS, programming used and size. –Boot sector virus –Polymorphic virus –Time Bomb –Shell virus –Add-on virus –Trojan horse –Internet worms

6. Polymorphic virus  Mutates  Hard to detect  All parts of the multipartite virus needs to be cleaned  Different kinds of damages Amusing screen displays Unusual sound displays System reboots Reformatting the hard disk

7. Shell Virus Uninfected Program Infected Program

8. Add-on Virus Uninfected Program Infected Program

9. Trojan Horse  A program that hides it true intention  e-mail attachments  Trick into installing malicious software –Droppers –Backdoors  Hackers –Subseven –Back Orifice –Netbus

10. Internet Worms  Use complex e-mal functions and network software  Steals addresses from your address book  New hosts through un-protected system drives  W32/ska W32/Navidad@MW32/Navidad@M  VBS/Netlog  W32/Explorezip  W32/Qaz  W32/SaddamHussain,……  Virus Hackers

11. Hackers attack Microsoft

12. Virus programmers  Common languages to create virus –Assembler –C–C –Visual Basic –Java  Unfortunately, virus are created by people for all usual reasons –Dirty tricks –Make a living  Fortunately, not all virus programmers aren’t in “ boy or girl genius league ”.

13. Viral Signatures  Repeated infection – early detection  Unique virus signatures  Mixed blessing –Fake Viral signatures to protect against virus

14. Why should I care ?  Reproduce –Stealing addresses from your Address Book –Write files to a Local directory / Network computer –Appears to be done by you  Un-authorized Access –Passwords –Credit card numbers –Destroy the computer –Computer un-usable  Allow other people (anywhere on internet), to get control of your computer

15. Have I Been a Victim ?  Reproduction stage  Alert box  Too late  Virus hoax are common than virus itself

16. Getting Rid of Virus  Virus code is tagged at the end of a program  Placed in the empty slots of a program  Both types can be cleaned  Unfortunately, virus world doesn’t end here  Some virus replace the program code with their own code  Can’t be cleaned, hence deleted

17. Getting Rid of Virus…  Some can be removed  Others may require part or all of the OS to be removed or re-installed  Retrieval of files  Damage cannot be undone

18. Prevention better than any cure  Technical measures –Anti-virus software –Update  Check mail-servers  Reject all e-mails of dangerous or unknown extensions  Suspect even safe extensions  Disabling functions  Removing windows script hosting

19. Do’s and Don’ts  A lways update your anti-virus software at least weekly  B ack up your important files and ensure that they can be restored  C hange the computer's boot sequence to always start the PC from its hard drive  D on't share Drive C: without a password and without read-only restrictions  E mpty floppy drives of diskettes before turning on computers, especially laptops  F orget opening unexpected e-mail attachments, even if they're from friends  G et trained on your computer's anti-virus software and use it

20. Do’s and Don’ts….  H ave multiple backups of important files  I nstall security updates for your operating system and programs as soon as possible  J ump at the chance to learn more about your computer. This will help you spot viruses  K nowledge is contagious, infect the truth

21. References  I’ll include them in the term paper ! Sampath Yerramalla