Microsoft · Exchange Server · CVE-2007-0039
**Name of the Vulnerable Software and Affected Versions**
Microsoft Exchange Server versions 2000 SP3 through 2007
**Description**
The issue is related to the handling of Internet Calendar (iCal) files, specifically when these files contain multiple X-MICROSOFT-CDO-MODPROPS (MODPROPS) properties. If the second MODPROPS is longer than the first, it can trigger a NULL pointer dereference and an unhandled exception, leading to a denial of service (crash). This can be exploited by sending an e-mail message with a specially crafted iCal file to a Microsoft Exchange Server user account, causing the mail service to stop responding.
**Recommendations**
For Microsoft Exchange Server versions 2000 SP3 through 2007, consider restricting access to calendar content requests until a fix is available.
As a temporary workaround, avoid using the `X-MICROSOFT-CDO-MODPROPS` properties in iCal files to minimize the risk of exploitation.