A malicious program or piece of programming code. A virus can can transmitted in a variety of ways, including being copied from one device to another through an infected thumb drive or being transmitted through an infected email attachment. Viruses can be as harmless as delivering a birthday message or as destructive as causing your hard drive to be reformatted.
A microorganism composed of a piece of genetic material - RNA or DNA - surrounded by a protein coat. To replicate, a virus must infect a cell and direct its cellular machinery to produce new viruses.
A small program written to alter the way a computer operates without the permission or knowledge of the user. A virus is self replicating with a potentially malicious program segment that attaches or injects itself into an application program or other executable system component and leaves no external signs of its presence, and usually programmed to damage system programs, delete files, create a denial of service, or reformat the hard disk.
A tiny organism that multiplies within cells and causes disease such as chickenpox, measles, mumps, rubella, pertussis and hepatitis. Viruses are not affected by antibiotics, the drugs used to kill bacteria.
A parasitic software program, equipped with the means of reproducing itself, that when executed, spreads throughout a computer or network by attaching itself to or infecting (modifying) other software or diskettes.
A computer program that can copy itself and infect a computer without permission or knowledge of the user. A virus might corrupt or delete data on a computer, use email programs to spread itself to other computers, or even erase everything on a hard disk.
A computer program or a portion of a computer program that is self-replicating when executed. The self-replicating capability permits the virus to spread throughout a computer system or network without detection. A virus is generally used to perform an unauthorized, visible, and sometimes destructive function such as displaying a message on computer terminals or erasing disk files.
Virus has been defined 34 different ways in documents like SANS Glossary of Terms, FFIEC IT Examination InfoBase, Glossary, Privacy & Security Glossary, and 7 more.