By Default Exchange Server 2010 allows internal hyperlinks access by using Android smart phones.
Users can access hyperlinks that indicates internal file server in your organization by clicking hyperlinks in emails.
In order to prevent this type of access follow the steps below;
Open Exchange Management Console -> drill down to server
configuration -> Client Access -> Exchange ActiveSync (middle tab)
-> right click on the name (default website in my case) properties
-> Remote file servers tab. From here, you can allow or deny access.