Vulnerability Note VU#978131

Microsoft Exchange 2000 system attendant sets incorrect remote registry permissions

Original Release date: 27 Sep 2002 | Last revised: 26 Mar 2003

Overview

The Microsoft Exchange System Attendant sets the permissions on a registry key incorrectly, allowing remote intruders access to the registry.

Description

The Microsoft Exchange System Attendant changes the permissions of the key:

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurePipeServers\winreg


to allow access to the members of the Everyone group. This change is made so that system administrators can manage the Exchange server through the Exchange System Manager Microsoft Management Console (MMC). The ACL on the key mentioned above is used to determine which users are able to use the standard remote registry management features. This permission also allows users to access the registry remotely. The change does not allow the intruder to bypass existing ACLs in the registry, so an intruder will still need to authenticate to the registry. If other registry keys have permissions that allow unauthenticated users to query values or make changes, the intruder will now be able to make those changes.

Impact

A remote intruder may be able to query or set registry key values remotely. The ACLs on the registry keys are still enforced correctly, but the ability for users to access the registry remotely may be undesired. If registry keys have weak permissions, data may be accidentally read or written.

Solution

Apply a Patch

Microsoft has produced patches to correct this problem. They patches are described in their advisory, which is available from:

Block Access to the Registry by Restricting SMB Network Access

Because the standard remote registry management features requires an SMB network connection, system administrators may wish to consider blocking ports 139/tcp and 445/tcp at their network perimeter.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Microsoft CorporationAffected07 Feb 200227 Sep 2002
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A

References

Credit

The CERT/CC was made aware of this vulnerability by Microsoft Security Bulletin MS02-003.

This document was written by Cory F. Cohen.

Other Information

  • CVE IDs: CAN-2002-0049
  • Date Public: 07 Feb 2002
  • Date First Published: 27 Sep 2002
  • Date Last Updated: 26 Mar 2003
  • Severity Metric: 4.62
  • Document Revision: 10

Feedback

If you have feedback, comments, or additional information about this vulnerability, please send us email.