Boot & Program Viruses

Boot & Program Viruses - Types and Habitats

Boot and program viruses were the first viruses. They are generally made of executable code that hides inside device boot programs and application programs, and are usually targeted for a specific computer operating system. These were the earliest types of computer viruses, and remained relatively common in the wild until overtaken in 1998 by script and macro viruses.
Boot viruses. Boot viruses hide in the boot code for a media device, such as a disk or CD, and run automatically when the media is loaded since boot programs are always the first code loaded from any device. Boot viruses proliferated on floppy disks and even CD's into the late 1990's, but aren't seen as often these days with the decline in importance of transferable, bootable media.
The first computer boot virus was built by a 15 year old kid namedRich Skrenta in 1982 for Apple II computers. Called “Elk Cloner”, it would activate whenever a floppy disk was booted on a computer, install itself on the computer, and then infect other disks used later. Once every 50 times an infected floppy was inserted in a computer it would display the following message.