Modern antivirus software tools and their capabilities

02

Boot sector viruses

Email viruses

Companion viruses

Macro viruses

Boot sector viruses

• alters or hides in the boot sector, usually the 1st sector, of a bootable disk or hard drive.
• contains code for bootstrapping programs (usually activates, but not necessarily, operating systems)
• Boot sector infector viruses replace the bootstrap code in the boot sectors (of floppy disks, hard disks, or both) with viral code.
• the BIOS on IBM PC compatible machines is ignorant of whether a disk has in fact been high-level formatted and had an operating system installed in it
• This results in a security vulnerability. A user who sees the error message may not be aware that the code in the boot sector of the disk has already been run by that point, and that if the disk was infected by a boot-sector computer virus