Q:

How do I stop this active malware alerted by Avast?

I am not knowledgeable on how to find adware/malware beyond scanning for it with whatever protection software I have. I avoid suspicious websites and often get popups from Avast if a page is infected and leave immediately. I recently have been receiving alerts that Avast stopped malware from:
http:// nano-adrouting-exchange (dot) info//Router//routing...
I could be just reading an article, not surfing, and the alert pops up. I have received 5 popups since they first began 3/2. I sense that some malware is actively trying to get through to my computer and I'm not sure how to stop it. 
I'm on Chrome on Mac if that helps.

A:

Lead developer of MacScan here! Hopefully I can shed some light on what I think is happening. I found a reference to the site you mentioned over on VirusTotal, and from other domains associated with that IP address it looks like this is the case of a fake antivirus alert scam popup. Basically, what happens is these scammers buy ad space on a number of sites (or through third party ad providers), and through the magic of javascript pop up an alert notifying you that your system is infected, and that you should call their 1-800 number to get it fixed.
Obviously, your system isn't really infected, but the pop-ups can be quite persistent, getting to the point of locking up your web browser by respawning the minute you close one out. If you call the 1-800 number, the scammers will have you install remote access software so they can take control of your system to "fix" the problem. They usually charge between $200 to $400 for this "service."
What I think is happening is that Avast has a content filter component, and is basically blocking those scam popups from appearing while you surf the web. Since the popups originate from ads on various websites, this would explain the behavior that you're seeing. If you're encountering the alert repeatedly on the same websites, you might want to e-mail the admin for the website and let them know that some of the ads they're serving are the scammy fake antivirus popups.
Hopefully this information can give you some peace of mind, but if you'd like to double-check for the presence of any adware or malware on your system causing problems, feel free to contact our support team and we'd be happy to investigate the issue further.

