Servlet Runtime Error Message Containing Sensitive Information

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

The following servlet code does not catch runtime exceptions, meaning that if such an exception were to occur, the container may display potentially dangerous information (such as a full stack trace).

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

  String username = request.getParameter("username");

  // May cause unchecked NullPointerException.
  if (username.length() < 10) {
    ...
  }

}

See Also