A vulnerability exists in Microsoft Windows DCOM/RPC that can be exploited to cause a denial of service. It may be possible for an attacker to execute arbitrary code on a vulnerable system.
Microsoft Windows Remote Procedure Call (RPC) "... is a powerful, robust, efficient, and secure interprocess communication (IPC) mechanism that enables data exchange and invocation of functionality residing in a different process. That different process can be on the same machine, on the local area network, or across the Internet." Distributed COM (DCOM) "...extends the Component Object Model (COM) to support communication among objects on different computers -- on a LAN, a WAN, or even the Internet."
Based on publicly available exploit code, there is a vulnerability in the way the RPCSS service handles DCOM/RPC messages. This vulnerability is different than those described in CA-2003-16 (VU#568148/MS03-026) and CA-2003-23 (VU#254236/VU#483492/MS03-039). As in the previous vulnerabilities, this flaw appears to occur in functions related to DCOM object activation. A remote attacker could attempt to exploit this vulnerability using crafted RPC packets.
An unauthenticated, remote attacker could cause a denial of service or possibly execute arbitrary code with SYSTEM privileges. In tests, the public exploit code crashes the RPCSS service on Windows 2000 and Windows XP systems patched with MS03-039. The exploit executes code on Windows 2000 systems that do not have the MS03-039 patch.
The CERT/CC is currently unaware of a practical solution to this problem.
Until patches are available, the following workarounds can be used to reduce possible attack vectors. These workarounds are not complete solutions and may affect network and application operation. Research and test before making changes to production systems.
This vulnerability was reported by 3APA3A (ZARAZA).
This document was written by Art Manion.
|Date First Published:||2003-10-14|
|Date Last Updated:||2003-10-15 17:02 UTC|