Microsoft Exchange is an e-mail server for Microsoft Windows operating systems.
A buffer overflow condition in the handling of the X-LINK2STATE extended verb could allow a remote attacker to execute arbitrary commands.
Install the patch referenced in Microsoft Security Bulletin 05-021.
Exploit works on Exchange 2000 SP3. Unauthenticated exploitation is not possible against Windows Server 2003. Since this is a heap-based buffer overflow, exploit may not be reliable. Automated penetration test might not be able to pick the correct Exchange target type since there is no way to determine it remotely.