What is the most typical kind of bug?
from web site
In computer system security, a virus is a type of malicious code or program that self-replicates by placing its code into other programs. A virus is a kind of malicious code or program that, when performed, reproduces by placing itself into other computer system programs, data files, or the boot field of the hard disk drive. Consequently, virus can spread out throughout a network of computer systems and cause significant damage.As a result, contaminated computers can spread out the infection to other computers. reference
