the most high-profile threats to informationintegrity is the computer virus.The most sophisticated threats to computersystems are presented by programs that exploit thevulnerabilities in computing systemsMalware has a mechanism to replicate andpropagate itself. The different types of malware are:Trap doors, logic bombs, trojan horses, viruses,worms and zombies.
Boot viruses: These viruses infect floppy disk. These viruses load into memory if thecomputer tries to read the disk while it isbooting.Boot sector viruses can be created withoutmuch difficulty and infect either the Master bootrecord of the hard disk or the floppy drive.
program viruses: They infect program files like files withextensions like .EXE, .COM , .BIN , .DRV and .SYS.Some file viruses just replicate while others destroythe program being used at that time.when executed they load the virus in thememory along with the program and perform thepredefined steps and infect the system
STEALTH VIRUSES: These viruses steals computers memory. They viruses are use various methods to hidethemselves and to avoid detection.
POLYMORPHIC VIRUSES: These viruses are more difficult to detectThey have the ability to mutate this means thatthey change the viral code known as the signatureeach time it spreads or infects.
macro viruses: A macro virus is a new type of computer virusthat infects macros with in a document.In essence, a macro is an executable programembedded in a word processing document or othertype of file. Typically users employ macros toautomate repetitive tasks and there by save keystrokes.
network virus: These viruses rapidly spreads throughLAN and internet. INTERNET LAN
Multipartite VirusesMultipartite viruses are the hybrid variety; theycan be best described as a cross between bothBoot Viruses and File viruses. They not only infectfiles but also infect the boot sector.
The ideal solution to the threat of viruses isprevention. Do not allow a virus is get into the system in firstplace. This goal is in general difficult to achieve, althoughprevention can reduce the no: of successful viral attacks..Detection: Once the infection has occurred, determine that ithas occurred and locate the virus.Identification: Once detection has been achieved, identify thespecific virus has infected a program.Removal: Once the specific virus has been identified, remove alltraces of the virus from the infected program and restore it to itsoriginal state. Advances in viruses and antivirus technology go hand inhand. As the virus arms race has evolved, both viruses andantivirus software have grown more complex and sophisticated
Usage of the “good-virus” in Centralized Anti-Virus Update:The person responsible for maintaining the virus protection has to go personally to eachcomputer and download the new version of the package manually from the server, the situationhas not improved very much.One segment of the worm will constantly monitor the logins. Each time a workstationsattempts to login, that segment automatically queries that workstation whether it is running theanti-virus product and which version of it.Affirmation to “good virus” Norms:It conforms to the Control requirement as the virus attempts to spread only on the computersattempting to access the network on which it is running.In fact, the replication code will not be copied, if they are not needed. The fact that it is a wormand spreads as a whole on the network makes it relatively easy to fulfill the requirement too.Since the "virus" modifies only old copies of itself and does not touch other programs, nocompatibility problems due to its virus-like behavior will occur.
Computer viruses are not evil and that programmers have aright to create them, posses them and experiment with them. But we should never support those people who writingviruses with destructive natureThus it can be effectively proved that it is possible to use theconcept of a virus for beneficial purposes.The future might use this technology for tedious and resourceconsuming jobs like software updates, system maintenanceand intruder detection.The “good viruses” are capable of annihilating their maliciouscounterparts
1. The Little Black book of Computer Viruses (electronic edition) By Mark A. Ludwig2. An Undetectable Computer Virus by David Chess and Steve White, presented at the Virus Bulletin Conference, September 2000 [PDF version]3. Fred Cohen, Computer Viruses - Theory and Experiments, Computer Security: A Global Challenge, Elsevier Science Publishers B. V. (North-Holland), 1984, pp. 143-158.4. Fred Cohen, Models of Practical Defenses against Computer Viruses, Computers Security, 8 (1989), 2, pp. 149-160.5. Nachenberg, C. “Computer Virus-Antivirus Coevolution.” Communications of the ACM.6. Computational Aspects of Computer Viruses by Fred Cohen7. Trends in Computer Virus Research by Fred Cohen8. Methodology of Computer Anti-Virus Research by Vesselin Bontchev