Computer Viruses :: essays research papers

A reckoner computer virus is a relatively small platform that attaches itself to data and broadcast shows before it delivers its malicious act. There are umteen distinct types of viruses and each one has a unique characteristic. Viruses are scattered up into to main(prenominal) classes, file infectors and system or rear-record infectors. A file infector attaches to ordinary programs usually affecting .COM and .EXE files. These two files are subject to contagious disease though some can infect any program from which exercise is requested. On the other spectrum, system or boot-record infectors infect executable enciphers appoint in certain system areas on a disk, which are non ordinary files.Not only are there two main classes of viruses, simply there are also many different types. A virus can be classified as a boot sector virus, a program virus, a trojan buck virus, a macro virus, a memory resident virus, a stealth virus, or a polymorphic virus. A boot sector virus rep laces the inauguration code on a disk with a modified version, which is wicked into the memory when the computer is started. Program viruses attach to legitimate program files. afterward attachment the program file leave alone because intercept the programs execution and take control of the computer system.Trojan horse viruses are also legitimate programs that are advertised as something desirable, but are actually something that is undesirable. It performs an unauthorized destructive act on your computer when executed. They received their name from the mythical Trojan Horse that was delivered to the gates of the urban center Troy.Macro viruses are written in macro language of precise computer programs, such as Word or Excel. These viruses infect files when a program document is accessed, or triggered by user actions, such as certain keystrokes or menu choices.Memory resident viruses hide in memory and are difficult to detect. When the virus is in memory it will infect any uni nfected file that is executed.A stealth virus hides their presence. They can infect a program by adding bytes to the infected file. It then subtracts the directory entry of the infected file by the same number of bytes. This gives the moving picture that the files size has not changed, therefore, antiviral programs can not detect them through these changes.Polymorphic viruses modify their appearance and scramble their code periodically. This allows them to replicate so that none of its copies are the same. These viruses also all turn in different characteristics.