A vulnerability exists in Microsoft's Remote Procedure Call (RPC) implementation. A remote attacker could exploit this vulnerability to cause a denial of service. An exploit for this vulnerability is publicly available.
Microsoft has released MS03-039 to address a vulnerability in Microsoft's Remote Procedure Call (RPC) implementation. A denial-of-service vulnerability exists in this service that can be remotely exploited. This vulnerability is not the same as the vulnerability described in CA-2003-16 (MS03-026), however, the impact is similar. An exploit for this vulnerability is publicly available. We have confirmed with Microsoft that this vulnerability only affects Windows 2000 systems.
A remote attacker could exploit this vulnerability to cause a denial of service. Although it has been reported that this vulnerability may be used to gain elevated privileges, according to Microsoft's testing, exploitation of this vulnerability can only cause a denial-of-service condition.
Microsoft has released a patch for this vulnerability in MS03-039.
You may wish to block access to from outside your network perimeter, specifically by blocking access to TCP and UDP ports 135, 139, and 445. This will limit your exposure to attacks. However, blocking at the network perimeter would still allow attackers within the perimeter of your network to exploit the vulnerability. It is important to understand your network's configuration and service requirements before deciding what changes are appropriate