I am running Avast 2015 free. I ran the network security test and when it had reached 100% the router disconnected. It immediately restored its connection and service was only briefly interrupted. Coincidence?
I have yet to install the 2015 version (haven’t yet been prompted by avast to do a program update and, frankly from the posts that I read here, I’ll probably wait a week or two). But I’m wondering if avast isn’t attempting to determine if your router setup is vulnerable to DNS rebinding malware. This attempts to access your router using JavaScript in a malicious web page. If the malware can login, it can change the router’s settings through the router’s config screens. You router doesn’t know if it’s you or a script in a web page trying to log into it. See:
http://www.antihacksecurity.com/the-news/93-dns-rebinding-attack-protection
(I use OpenDNS despite I dislike they redirect what should be failed DNS lookups to their “helper” page.)
The fix is to NOT use the default login credentials for the router as it comes delivered from the factory or after a reset to factory defaults. Most, maybe all, routers don’t prompt to change to a strong password when you first login to the router’s internal web server to see its config screens (and many ignore the username entry so that’s bogus and only the password is used to determine it you can login or not).
So change the password to login into your router away from the default one (factory-time default). Make sure avast cannot log into your router so that malware also cannot log into your router.
So change the password to login into your router away from the default oneGood advice. This is something that everyone should do. The problem however is that most(?) people get the router from their ISP with non standard firmware. Better is perhaps even to flash the firmware with the latest original firmware from the manufacturer since almost all isp's have a "backdoor account"