Viruses, spyware, malware: sorting out the bad guys

Every week another product comes out declaring it’s the best around to knock out spyware. Or it’s the best not just for spyware, but for malware, viruses and adware.

What is the difference among those terms — malware, virus, adware and spyware?

A virus is a computer program that infects other programs with its own code. When an unsuspecting user starts a virus-infested computer program, the virus looks for more programs to infect. A worm is one type of virus; it can infect your machine without launching a specific program.

Spyware is a catch-all term for a variety of non-virus malicious software. It specifically refers to programs that, when launched, spy on activity. Spyware tracks personal information and e-mails it to some other site, usually for nefarious purposes.

A subgroup of spyware, keyloggers are programs that record the keys you type, thereby capturing passwords and other sensitive data.

Malware is the all-encompassing term for malicious programs, ranging from spyware and keyloggers to adware. Malware also includes deceitful programs, such as stealthy screensavers. When activated, instead of just providing screen images, such programs also load ads or pop up warnings — falsely reporting the computer is infested with a virus — which can be removed only by buying some recommended product.

The term adware refers to programs that display ads on your computer (independent of the built-in banner ads on Web sites). They can be benign but sometimes are difficult to eradicate. If nothing else, they consume computer CPU cycles and degrade performance.