Which application is switching on wifi? I am running Android 4.3 on a Samsung Galaxy S3, switching on or off WiFi on a need-to-use basis. A few days back, I realized that WiFi would spontaneously be switched on. I switched it off, but it would be switched on again.

I probably have downloaded an app or an update that is the reason for that behaviour. After trying to uninstall a number of these apps (no result up to now), I am wondering whether there is a possibility to log which app does what on the wifi connection, so as to identify the culprit.

I tried WIFi Fixer and saw a log line (among many others) that said:


  Failover set to: www.baidu.com 


This makes me thinks the culprit tries to go to baidu (I have never connected to baidu). Avast scan does not detect a virus, so I am stuck.
In china GCM (and many other Google services) are blocked by government. In order to send push notification to app in China there are multiple local service providers. One of them is Baidu, the link you are seeing in the logs.
Possible that some app is using that, instead of GCM.