1. A non-transitory computer-readable medium having stored thereon an agent component that is configured to be installed on a mobile device of a user to provide secure access over a network to an enterprise resource of an enterprise system, the agent component comprising executable code that implements a process that comprises: intercepting, by the agent component installed on the mobile device, a hypertext transfer protocol (HTTP) request generated by an application installed on the mobile device; modifying the HTTP request by replacing a hostname of the HTTP request with a hostname of the enterprise resource; encapsulating, by the agent component installed on the mobile device, a representation of the modified HTTP request according to a tunneling protocol; and sending, by the agent component installed on the mobile device, the encapsulated representation of the HTTP request from the mobile device over a network to a tunnel mediator that is configured to extract and forward the representation of the HTTP request to a corresponding enterprise resource, wherein the agent component is configured to send the encapsulated representation of the HTTP request using a tunnel definition that is specific to the application installed on the mobile device.