PUP.Optional.Babylon.A, Firefox and Malwarebytes - false positive or what?
For a while now, every time, or pretty near every time, I run a full Malwarebytes scan on my computer it reports an infection of PUP.Optional.Babylon.A in the form of a file ...\\AppData\Roaming\Mozilla\Firefox\Profiles\asp4l5mt.default\prefs.js . Actually, this shows up as four “items”, but they all seem to be the same file. Malwarebytes offers me the options of ignoring, excluding or quarantining the items, and I always choose quarantine, which Malwarebytes seems to do quite happily, but the same “items” always seem to be there again, unquarantined, next time I run Malwarebytes. (I usually do so after any time I inadvertently visit a web site that seems fishy, but, apart from this issue, Malwarebytes almost never seems to find any infection, and when it has, it has, otherwise, been able to clean things up without trouble).
I Googled PUP.Babylon.A and it seems to be a fairly innocuous piece of adware, quite easy to remove, that redirects your search, but I have not seen any searches getting redirected, or noticed any other sort of performance problem or odd behavior.
So, what is going on? Is this some sort of false positive reacting to a component of Firefox? Given that I have seen no actual problems, or odd behavior, that is the assumption I have been going on, but I would have thought, if that were so, a lot of people would be seeing it, and Malwarebytes would have fixed the issue in an update by now. Could it be one of my Firefox extensions giving a false positive? Or is it likely to be a real infection? If the latter, what might it really be, and what can I do about it?
It is the free Malwarebytes, version 22.214.171.1242, and I always update the definitions before scanning. I am on Windows 7 Home Premium 64 bit (up to date), and, currently, Firefox 32.03 (which I also keep up to date - but this issue has now persisted through several Firefox versions and many Windows Updates). Microsoft Security Essentials does not find any problems.