Software Engineering Institute

Microsoft Collaboration Data Objects (CDO) is a scripting library used to develop applications that handle email. Note that CDO is commonly associated with cdosys.dll and codex.dll. An input validation error in CDO may allow a buffer overflow to occur in applications or components that use CDO. If a remote, unauthenticated attacker supplies an application or component that uses CDO with a specially crafted message, that attacker may be able to trigger the buffer overflow and, consequently, execute arbitrary code.

For more information, including a list of affected software, please see MS05-048. Please note that exploit code for this vulnerability is publicly available.

If a remote attacker supplies an application that uses CDO with a specially crafted message, that attacker may be able execute arbitrary code on a vulnerable system.

Apply an update

Microsoft has addressed this issue in Microsoft Security Bulletin MS05-048.

In addition, MS05-048 suggests the following workarounds:

Disable event sinks on Exchange 2000 Server and on servers that are running IIS

Disabling all event sinks will help protect the affected system from attempts to exploit this vulnerability. For instructions on how to disable event sinks, please refer to MS05-048.

Unregister cdoex.dll file and the cdosys.dll

Unregistering cdoex.dll and cdosys.dll will will reduce the chances of exploitation. Again, for instructions on how to unregister DLLs, please refer to MS05-048.