Fake anti-virus malware reports non-existent threats in order to scare the user into paying for unnecessary product registration and cleanup.
Fake anti-virus malware is commonly known as scareware. Typically it is installed through malicious websites and takes the form online scans. Cybercriminals attract traffic to these sites by sending out spam messages containing links or by compromising legitimate websites. Frequently they also attempt to poison the results of popular search engines so that users access the malicious distribution sites when conducting a search.
Fake anti-virus malware is financially motivated and is a big earner for cybercriminals. The large profits enable significant resources to be invested into its creation and distribution. Hacking gangs are proficient at rapidly producing professional-looking bogus websites that pose as legitimate security vendors.
Using up-to-date, legitimate anti-virus or endpoint security software will protect you against fake anti-virus software.