Types of Viruses

Boot Sector Infectors: The boot program, you get a boot sector virus by leaving an infected diskette in a drive and rebooting the machine. When the boot sector program is read and executed, the virus goes into memory and infects your hard drive. File Infectors: These are viruses that attach themselves to, or replace .COM and EXE files.( in some cases they can infect files with other extensions) File Infector virus' infect uninfected programs when they are executed in memory. In other cases they are infected when they are opened, occasionally the virus simply infects all of the files in the directory it was run from. The file-infector class is also used to refer to programs that do not physically attach to files but associate themselves with program files names. Master Boot Record Infectors: Infects the system's Master Boot Record on hard drives and the Boot Sector on floppy diskettes. This type of virus takes control of the system at a low level; activating between the system hardware and the operating system. A Boot Sector virus is loaded into memory upon boot-up, before virus detection code can be executed. Macro Virus: Some computer applications contain macro languages to help automate tedious tasks. As computers have grown more powerful, the tasks have become more complex. Some macro languages offer the ability to write files other than the original document. This feature may be used by virus authors to create unwanted macros, which "infect" documents. Macro virus' are typically spread through MS Word & Excel files. Multi-partite Viruses: Multi-partite viruses are a combination of the viruses listed above. cuted. Polymorphic viruses: They are coded in such a way that they infect a system and change their signature. Worms: Worms are program that replicate and spread to other system. Trojans: A Trojan is a program file that claims to do something but it actually does something that is not required.