Software Engineering Institute

Microsoft's Network Dynamic Data Exchange (NetDDE) is a communication protocol that allows two Windows applications to communicate with each other over a network. A buffer management flaw exists in the way that this service handles certain malformed messages. This flaw results in a vulnerability that could allow an attacker to compromise the system. According to Microsoft security bulletin MS04-031:

A remote code execution vulnerability exists in the NetDDE services because of an unchecked buffer. An attacker who successfully exploited this vulnerability could take complete control of an affected system. However, the NetDDE services are not started by default and would have to be manually started for an attacker to attempt to remotely exploit this vulnerability.

This bulletin also states:

There are cases when Microsoft Excel could also use NetDDE. Microsoft Knowledge Base Article 128941 discusses how Microsoft Excel can use NetDDE.

A remote unauthenticated attacker may be able to execute arbitrary code with administrative privileges on the affected system. Microsoft reports that this vulnerability could also be used to attempt to perform a local elevation of privilege or remote denial of service.

Apply a patch from the vendor

Microsoft has published Microsoft Security Bulletin MS04-031 in response to this issue. Users are strongly encouraged to review this bulletin and apply the patches it refers to.

Workarounds

In addition to the patches referenced above, Microsoft has published workarounds for this issue. Users who are unable to apply the patches are strongly encouraged to implement these workarounds as appropriate. Microsoft states explicitly:

Third-party applications may also require the NetDDE services; therefore it is important to test the suggested workarounds in your organization before you deploy this update.