We were getting reports from some users, specifically on mobile, who were getting javascript confirms popping up over the entire page, showing a url from adnxs
Now we are old timers and we know immediately to question if their phone/tablet is infected with a bad app, router possibly being manipulated, etc.
So we took out a tablet, formated it fresh with new android install, google app store is not even installed, no apps.
Fired up the browser on it and started browsing the site.
Within 10 minutes we got the same javascript confirm.
It is NOT embeded in our website source, we have not been hacked, we've examined it at the "view selected source" level.
I do see a pattern though.
"Clean Master" ads seem to be involved and they do seem to be coming from google adsense.
Has a new hack leaked into google adsense that they are not catching?