There is a new WordPress attack going around and in the past two weeks it has taken off, infecting 5000 sites per day:
Its goal apparently is to redirect visitor browsers to a site that attempts all the latest breach hacks so their computer can be further compromised.
Scan your files (and perhaps database) for “visitorTracker_isMob”
grep -r "visitorTracker_isMob" *
or perhaps more specifically only .js files
grep "visitorTracker_isMob" -ri --include \*.js