Improving Web Application Security: Threats and - CGISecurity

Chapter 14: Building Secure Data Access 371CountermeasuresTo prevent disclosure of sensitive application data:● Use strong encryption to secure the data.● Authorize each caller prior to performing data access so that users are only able tosee their own data.Disclosure of Database Schema and Connection DetailsIf your code returns exception details to the client, a malicious user can use theinformation to attack the server. Exceptions in data access code can reveal sensitiveinformation, such as database schema details, the nature of the data store, and SQLcode fragments.VulnerabilitiesThe following vulnerabilities can result in information disclosure:● Inadequate exception handling● Weak ASP.NET configuration that allows unhandled exception details to bereturned to the clientCountermeasuresTo prevent such disclosure:● Catch, log, and handle data access exceptions in your data access code.●Return generic error messages to the caller. This requires appropriateconfiguration of the element in the Web.config or Machine.configconfiguration file.Unauthorized AccessWith inadequate authorization, users may be able to see another user’s data and maybe able to access other restricted data.VulnerabilitiesPractices that can allow unauthorized access include:● Lack of authorization in data access code providing unrestricted access● Over-privileged database accounts