CERT® Advisory CA-2003-03 Buffer Overflow in Windows Locator ServiceOriginal issue date: January 23, 2003
Last revised: January 24, 2003
A complete revision history is at the end of this file.
A buffer overflow vulnerability in the Microsoft Windows Locator service could allow a remote attacker to execute arbitrary code or cause the Windows Locator service to fail. This service is enabled and running by default on Windows 2000 domain controllers and Windows NT 4.0 domain controllers.
A buffer overflow in the Windows Locator service may make it possible
for a remote attacker to execute arbitrary code on a vulnerable system
by sending an overly large request to the Windows Locator
service. Microsoft describes the Windows Locator service as "a name
service that maps logical names to network-specific names." From
A client that is going to make a Remote Procedure Call (RPC) can call the Locator service to resolve a logical name for a network object to a network-specific name for use in the RPC. For example, if a print server has the logical name "laserprinter", an RPC client could call the Locator service to find out the network-specific name that mapped to "laserprinter". The RPC client uses the network-specific name when it makes the RPC call to the service.Further information about this vulnerability can be found in Microsoft Security Bulletin MS03-001 and in CERT/CC Vulnerability Note VU#610986, which correspond to CVE candidate CAN-2003-0003.
A remote attacker may be able to execute arbitrary code on a vulnerable system, or cause the Windows Locator service to fail. An attacker who is able to compromise a domain controller might be able to cause the compromised domain controller to trust the attacker's domain.
Apply a patchMicrosoft has provided the following information (contained within MS03-001) to assist you in downloading the appropriate patch for your platform(s):
Disable vulnerable service
Until a patch can be applied, you may wish to disable the
Windows Locator service. To determine if the Windows Locator service
is running, Microsoft recommends
To disable the Windows Locator service, Microsoft recommends the following:
Restrict access to NetBIOS
You may wish to block access to NetBIOS from outside your network perimeter, specifically by blocking access to ports 139/TCP and 445/TCP. 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.As a best practice, the CERT/CC recommends disabling all services that are not explicitly required. Before deciding to disable the Windows Locator service, carefully consider your service requirements. Please also note that Microsoft is actively deploying the patches for this vulnerability via Windows Update.
Appendix A. Vendor Information
This appendix contains information provided by vendors. When vendors report new information, this section is updated and the changes are noted in the revision history. If a vendor is not listed below, we have not received their comments.
Appendix B. References
Author: Ian A. Finlay.
This document is available from: http://www.cert.org/advisories/CA-2003-03.html
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Copyright 2003 Carnegie Mellon University.
January 23, 2003: Initial release