Microsoft Download Center: Microsoft Anti-Cross Site Scripting Library V4.2
The Microsoft Anti-Cross Site Scripting Library V4.2 (AntiXSS V4.2) is an encoding library designed to help developers protect their ASP.NET web-based applications from XSS attacks. It differs from most encoding libraries in that it uses the white-listing technique -- sometimes referred to as the principle of inclusions -- to provide protection against XSS attacks. This approach works by first defining a valid or allowable set of characters, and encodes anything outside this set (invalid characters or potential attacks). The white-listing approach provides several advantages over other encoding schemes.
This release addresses a vulnerability in the HTML Sanitizer, MS12-007 and adds full support for .NET 4.0 as well as restoring support for .NET 2.0.