Ads by StartApp
So last week I started getting popups on my phone. No matter what program I'm in, or what I'm doing, randomly the screen will dim and a revolving ad will appear. Lower left corner is an info button that when clicked rolls out and says "Ads by StartApp" and the upper left is a close icon. I've downloaded Ad Detector, and Avast!Mobile Security and neither of them find anything even though Google says that they should be able to find apps with StartApp attached.
So has anyone here seen this? I hadn't installed any software shortly before it started happening. I've tried uninstalling everything that I've downloaded in the last few months. I'd prefer not to have to completely wipe my phone because I have GoodForEnterprise and the service desk is a PITA when you have to get a new pin for it.
Specs: Galaxy S4 Android 4.4.2