At the office I noticed malware symptoms on one of the computers. I tried cleaning it and found nothing. Then I noticed I got the same behavior on my phone and the other computer: occasional links would redirect to malware download pages.
I changed my phone to cellular data and the behavior went away. I figured it must be the router or cable modem. I power cycled them and checked for a proxy or any other strange settings. I didn't see any, and it worked normally for a while, only to return again later.
What am I missing? Where else could the malware be coming from?