Malware Testing Problem

This morning I tried some tests of links on Malware Domains List. After one of the tests, I think it may have been ransomware but not sure, I noticed a bit of a slowdown, so I terminated the virtualbox session and restored to my baseline image from 3 days ago and which has no issues.

Unfortunately even after restoring I noticed that I could no longer connect to the web within the XP within the virtualbox (on linux mint), and also subsequently discovered that I could also no longer connect with linux even with VB closed! I also rebooted a couple of times.

The connection gets as far as the Zyxel router, and the line looks clear, but it will not connect to a web address. When I dual boot back into Win 7 the connection is OK.

I am new to testing, so a question to all you experienced folk out there, can linux which hosts the VB, or even the router itself, be attacked or get malware from malware tests running within a virtual session under linux?! If so, how can a router be checked for malware? For checking linux I will run a linux AV scan, but I am concerned about rootkits or whatever not being detected.

Any suggestions or links appreciated, thanks.

For future testing, any suggestions on how to better protect myself is also appreciated! By the way, the router settings such as DNS etc do not appear to have changed (still showing the Open DNS ips), and it is protected by a good password, so I reckon it may not have been breached but linux may have?