Microsoft Security Bulletin (MS00-064)
Patch Available for "Unicast Service Race Condition" Vulnerability
Originally posted: September 06, 2000
Microsoft has released a patch that eliminates a security
vulnerability in Microsoft(r) Windows Media(tm) Services. The
vulnerability could allow a malicious user to prevent an affected
server from providing useful service.
Frequently asked questions regarding this vulnerability and the patch
can be found at
If a client sends a particular type of malformed request to a Windows
Media server, it could induce a race condition. Once the server has
been put into such a state, subsequent requests - even ones that
would normally be legitimate - could cause the Windows Media Unicast
Service to fail. If this happened, any ongoing sessions would be
lost, and the server would stop providing unicast streaming media
An affected server could be put back into service by restarting the
Unicast Service. The vulnerability would not cause any data loss, nor
would it enable the malicious user to usurp any administrative
privileges on the machine.
Affected Software Versions
- Microsoft Windows Media Services 4.0
- Microsoft Windows Media Services 4.1
- Microsoft Windows Media Services 4.1:
Note: Customers using Windows Media Services 4.0 should upgrade to
Windows Media Services 4.1 and then apply the above patch.
Note: Additional security patches are available at the Microsoft
Please see the following references for more information related to
- Frequently Asked Questions: Microsoft Security Bulletin MS00-064,
- Microsoft Knowledge Base article Q273014 discusses this issue
and will be available soon.
- Microsoft TechNet Security web site,
Obtaining Support on this Issue
This is a fully supported patch. Information on contacting Microsoft
Product Support Services is available at
Microsoft thanks Kit Knox of NaviSite (www.navisite.com) for
reporting this issue to us and working with us to protect customers.
September 06, 2000: Bulletin Created.