security - Can Applications With Root Access Modify Their Own Permissions?

For rooted phones, there are several apps which require root privileges. Knowing this, the user does allow the app to get root. Now, the app would have been installed with a set of x permissions, say INTERNET, LOCATION. Now, on gaining root, is it possible for the app to secretly (or not) give itself extra permissions eg. BLUETOOTH ? I read somewhere that the Apps requiring INTERNET or BLUETOOTH permissions are added to a user group which has access to these device files. So, can a rooted app associate itself to that group and gain the permission ?

Answer

Yes, all rooted apps theoretically can use the entire system, including all facilities that otherwise need app permissions. They could also modify the permissions database "under the radar" to grant its non-root part more permissions than were requested at install time.

You have to trust root-using apps not to violate their given permissions.