They are usually disguised as a legitimate program or file.

Since viruses masquerade as sections of legitimate programs, they're tough to detect.

The page lists links to proven and legitimate antispyware programs.

Early viruses were pieces of code embedded in a larger, legitimate program, such as a game or word processor.

It would need to take steps against nuclear proliferation without running roughshod over the sovereignty of nations with legitimate nuclear programs.

This method is less common as the malware is likely to be detected by legitimate anti-malware programs.

We have a good program, a legitimate program.

Then there are the legitimate programs that have been infected with subprograms called viruses .

For this reason, many viruses attach themselves to executable files that may be part of legitimate programs (see code injection).

Advertising and an attractive interface are not an indication of a legitimate program.