Microsoft Security Bulletin MS03-026 Print


Buffer Overrun In RPC Interface Could Allow Code Execution (823980)
Originally posted: July 16, 2003

Revised: July 21, 2003

Summary
Who should read this bulletin: Users running Microsoft ® Windows ®

Impact of vulnerability: Run code of attacker’s choice

Maximum Severity Rating: Critical

Recommendation: Systems administrators should apply the patch immediately

End User Bulletin: An end user version of this bulletin is available at:

http://www.microsoft.com/security/security_bulletins/ms03-026.asp.

Affected Software:

Microsoft Windows NT® 4.0
Microsoft Windows NT 4.0 Terminal Services Edition
Microsoft Windows 2000
Microsoft Windows XP
Microsoft Windows Server™ 2003
Not Affected Software:

Microsoft Windows Millennium Edition

Microsoft originally released this bulletin and patch on July 16, 2003 to correct a security vulnerability in a Windows Distributed Component Object Model (DCOM) Remote Procedure Call (RPC) interface. The patch was and still is effective in eliminating the security vulnerability. However, the “mitigating factors” and “workarounds” discussions in the original security bulletin did not clearly identify all of the ports by which the vulnerability could potentially be exploited. We have updated this bulletin to more clearly enumerate the ports over which RPC services can be invoked, and to ensure that customers who have chosen to implement a workaround before installing the patch have the information that they need to protect their systems. Customers who have already installed the patch are protected from attempts to exploit this vulnerability, and need take no further action.

Remote Procedure Call (RPC) is a protocol used by the Windows operating system. RPC provides an inter-process communication mechanism that allows a program running on one computer to seamlessly execute code on a remote system. The protocol itself is derived from the Open Software Foundation (OSF) RPC protocol, but with the addition of some Microsoft specific extensions.

There is a vulnerability in the part of RPC that deals with message exchange over TCP/IP. The failure results because of incorrect handling of malformed messages. This particular vulnerability affects a Distributed Component Object Model (DCOM) interface with RPC, which listens on RPC enabled ports. This interface handles DCOM object activation requests that are sent by client machines to the server. An attacker who successfully exploited this vulnerability would be able to run code with Local System privileges on an affected system. The attacker would be able to take any action on the system, including installing programs, viewing changing or deleting data, or creating new accounts with full privileges.

http://www.microsoft.com/technet/treeview/?url=/technet/security/bulletin/MS03-026.asp