Antivirus-defence.com Claims False Malware Infection
Antivirus-defence dot com is a very plain misleading website, put together with the sole purpose of shoving intrusive and potentially dangerous ads in your browser.
Landing on Antivirus-defence dot com, users are shown a fake antivirus dialog box. This is just an image skinned and styled to resemble an antivirus app. The text on the image will claim that your system is infected because you "visited illegal infected website".
The horrible grammar visible throughout the warning message should serve as the first red flag. The next one should be a ransom website telling you your system is infected. Remember that no web page can know the security or infection status of your system. All those messages always just attempt to scare or possibly also defraud you.
The site will also attempt to push ads in your browser using push notifications. Such ads may be unsafe, as misleading websites work in conjunction with rogue ad networks very often. This means the ads sourced through the rogue network may lead to all sorts of nastiness, including questionable adult content, scam or phishing pages, other misleading websites or potentially unwanted app installers.
Simply close your browser when you see this sort of fake warning and you will avoid all of those issues.