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Article: Q283618
Product(s): Microsoft SourceSafe
Version(s): 4.0,5.0,6.0
Operating System(s): 
Keyword(s): kbConfig kbDSupport kbGrpDSSSafe
Last Modified: 06-JUL-2001

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The information in this article applies to:

- Microsoft Visual SourceSafe, 16-bit, for Windows, versions 4.0, 5.0 
- Microsoft Visual SourceSafe, 32-bit, for Windows versions 4.0, 5.0, 6.0 
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SUMMARY
=======

Visual SourceSafe provides a "Use network name for automatic user log in" option
that allows Visual SourceSafe integration with Microsoft Visual InterDev or
Microsoft FrontPage. However, the feature has security ramifications that users
should consider before using it. Microsoft recommends that the feature only be
used in protected networks in which all users are fully trusted.

MORE INFORMATION
================

The "Use network name for automatic user log in" option in Visual SourceSafe is
designed to enable single sign-on to development environments. When the option
is selected (this is the default), Visual SourceSafe uses the currently
logged-in account name as the Visual SourceSafe user name. If the name matches a
Visual SourceSafe user name, the user is logged in without a password.

Use of this feature can provide a better user experience by not requiring the
user to enter a userid and password repeatedly. However, there are security
ramifications associated with using the feature, and customers should consider
them carefully before using it:

- The feature does not perform Windows authentication, in which
  cryptographically protected credentials are exchanged anytime the user
  requests access to a resource, even through single sign-on mechanisms.
  Instead, the feature sends the current account name, which Visual SourceSafe
  then compares to a local database of users.

- It could be possible for a user to log in as any desired Visual SourceSafe
  user, simply by logging into a local account with a userid that exists in
  Visual SourceSafe. In particular, there is always a user name of "Admin" in
  the Visual SourceSafe user list, which has full administrative access and
  cannot be deleted. If the Use network name for automatic user log in feature
  is enabled, an attacker could create a local machine account named "Admin",
  and then misuse the automatic log in feature to gain access to the Visual
  SourceSafe "Admin" account.

- The feature can be disabled, but it is possible for the client to override
  the server settings and re-enable it.

Because of these factors, Microsoft recommends that the "Use network name for
automatic user log in" feature only be used in protected networks in which all
of the users are fully trusted. It should not be used on unprotected networks or
networks containing users who require differing levels of privileges. Indeed,
Visual SourceSafe itself is not recommended for use on unprotected networks, as
it is a development tool.

The most effective way to provide security for Visual SourceSafe is by
controlling access to the share on which the server software and the database
reside. This can be done by setting NTFS permissions on the share and, if
appropriate, hiding the share.

Conclusion
----------

There can be significant benefit to enabling the "Use network name for automatic
user log in" option in a protected network. However, in an unprotected network,
this option is not appropriate.

REFERENCES
==========

If you require technical assistance with this issue, contact Microsoft Product
Support Services:

  http://support.Microsoft.com/support/contact/default.asp

Additional query words:

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Keywords          : kbConfig kbDSupport kbGrpDSSSafe 
Technology        : kbSSafeSearch kbAudDeveloper kbSSafe600 kbSSafe400 kbSSafe500 kbSSafe16bitSearch kbSSafe32bitSearch
Version           : :4.0,5.0,6.0
Issue type        : kbinfo

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Q283618: INFO: Security Considerations When Using Automatic User Login