Spent the last 3 days trying to figure out what on my PC is causing a denial of service attack to my router. What is happening is the DNS server through the router/firewall is getting nailed at once with 1000 DNS queries, sees it as an attack (rightfully so) and locks out the port. I recognize the list and it looks like the Alexa Top 1000.
So I performed a boot scan with Avast, scanned with Malwarebytes, Spybot, Windows Defender, Microsoft Safety Scanner and the MS Malicious Software Removal tool. Wiped most programs off the PCs, scoured regedit/msconfig boot process and used CCleaner. Nothing found.
I tried to find it using Process viewers but still can't find it since it is so illusive. Turns out it waits until the PC goes to screen saver, idle or comes out of sleep. When I try to view the process that is doing it my network logs show it stops right when I touch the keyboard. Was just getting ready to reinstall Windows at this point.
I just found another thread here back in January that has one post mentioning Alexa Top 1000 and Avast Secure DNS. I am however using the free version so I am not using secure DNS but is this Avast Free behavior with version 10.2.2218?