Microsoft Security Bulletin (MS00-058) - Microsoft has released a patch for the "Specialized Header" security vulnerability in Internet Information Server (IIS 5.0) that ships with Windows 2000. The vulnerability causes a web server to send the source code of certain types of web files to a visiting user. Microsoft FAQ on this issue available here.
ffb426bb0a7ba1499d38ac3b01b2c19dd310421d100dd0f99c96880a7b7fca7a