Ads security issue affecting all Android system for a couples of day I have noticed that there is a strange behavior on my Android phone device. and I think it is a global problem.

I have noticed that some Ads appears in the screen in whatever app is opened or on the home screen, with and X to close it. It could appear overlapping any application, and in the middle of the screen but not full screen.

I closed it, and I didn't know what application causing that behavior, but after a while I have noticed that some application are installing them self without any permission from my side. those application are four and appears on the notification bar with  is downloading themself. and the phone is going so slow.

I check the apps manager and I found four strange services I didn't notice them before. 


adService
Clain Left
com.android.tools
com.bd.sdk.project


I uninstall them and they return again and again every one or two hours. and in different Wifi network.

I decided to rest my phone to its factory setting. but I still got the same problem.!!!

Dose somebody faced that kind of problem recently? and what solve this problem.
Thanks
it keeps reappearing because you are not removing the problem causing potentially unwanted program. You probably have something from that category and these intruders are not that easy to remove. You uninstall only the feature that annoys you but not the problem itself. Especially since you can see there is not one program appearing.
You should rely on anti-malware tools and remove possible threats, intruders, cyber infections. There is a few available online for free. You can find them on the App Store. Those programs can detect, remove and even block threats later on. 
These additional programs come from insecure ads, websites, installations. So you can't see when they were downloaded exactly and the ones on your browser are not the main program that causes problems.