Originally Posted by venkss
Any help please?
Apps that are not running should not use data; but there are other things that do.
Widgets use data - do you have a weather widget? News, social networks, contacts or calendar?
Gmail, Exchange, AT&T - all have address book and calendar sync that is going on and constantly checking for changes. 3rd party apps with ads should not be a concern - they should not be using data when not running.
As for security risk - it depends as i don't know what apps you have installed. When you install an app it indicates what it has access too. If a checkers app has access to contacts, phone, and gps then i would be concerned.