Title: Authentication Flaw in Microsoft Metadirectory Services
Could Allow Privilege Elevation (Q317138)
Date: 24 July 2002
Software: Microsoft Metadirectory Services 2.2
Impact: Elevation of privilege
Max Risk: Medium
Bulletin: MS02-036

Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS02-036.asp.

Issue:

Microsoft Metadirectory Services (MMS) is a centralized metadirectory
service that provides connectivity, management, and interoperability
functions to help unify fragmented directory and database
environments. It enables enterprises to link together disparate data
repositories such as Exchange directory, Active Directory,
third-party directory services, and proprietary databases, for the
purpose of ensuring that the data in each is consistent, accurate,
and can be centrally managed.

A flaw exists that could enable an unprivileged user to access and
manipulate data within MMS that should, by design, only be
accessible to MMS administrators. Specifically, it is possible for
an unprivileged user to connect to the MMS data repository via an
LDAP client in such a way as to bypass certain security checks.
This could enable an attacker to modify data within the MMS data
repository, either for the purpose of changing the MMS
configuration or replicating bogus data to the other data
repositories.

Mitigating Factors:

• If normal security practices have been followed, the
  vulnerability could not be exploited from the Internet.

• The vulnerability could only be exploited by an attacker who had
  significant technical expertise at a protocol level. The
  vulnerability does not provide access to MMS itself, but rather to
  the MMS data repository. Determining what data to change - and how
  to change it - in order to cause a desired effect could be
  quite difficult

• A successful attack would require a detailed understanding of the
  specific way MMS had been configured, as well as information about
  all of the other directories and database it was being used to
  manage. It is likely that the vulnerability could only be
  exploited by an attacker who had insider knowledge about the
  enterprise.

Risk Rating:

• Internet systems: Moderate
• Intranet systems: Moderate
• Client systems: None

Patch Availability:

• A patch is available to fix this vulnerability. Please read the
  Security Bulletin at
  http://www.microsoft.com/technet/security/bulletin/ms02-036.asp
  for information on obtaining this patch.

Acknowledgment:

• Pascal Huijbers and Thomas de Klerk of Info Support
  http://www.infosupport.com/

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