Adware is software that is designed to display advertisements on your computer or mobile device. Adware is different from malware or viruses because adware by itself isn’t always used by cybercriminals; there are legitimate, harmless uses for adware. Adware that is legitimate and harmless is usually found in conjunction with free apps where you consent to see ads in exchange for getting the app for free or at low cost. But adware can also sometimes be a problem for you. Cybercriminals can try to put adware on your system that you don’t want (often as part of a virus or malware attack) or don’t consent to (very often showing you ads for pornography or financial scams). And malicious adware can often also have spyware, Trojan horses, keystroke loggers, viruses or other malware silently included without you knowing. While good adware can enable you to enjoy apps for free, bad adware can turn your system into a zombie computer that is part of a botnet and is sending out spam, phishing emails, and even attacking other computers.
Malicious adware is essentially the same as a virus because you get it on your system or device without wanting to. Because of this, the best way to protect yourself from malicious adware is by running up-to-date antivirus software and security packages. Security companies keep their products current with information on the latest malicious adware. They also help protect you against other types of malware that malicious adware can sometimes install on your system. Perhaps most importantly, though, is that security software is able to tell if a particular piece of adware is legitimate or not and leave the legitimate adware alone. This means that with a good security software system, you can enjoy the benefits of legitimate adware (free or low cost apps supported by appropriate, meaningful ads) and still be protected against the dangers of malicious adware.