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 Last Updated: March 19, 1996

 Microsoft wants its customers to know that it has discovered and fixed a
 potential security problem with file and printer sharing in Microsoft®
 Windows® 95. Only customers who have enabled file and printer sharing—a
 non-default option—may have been at risk, and, to the best of our
 knowledge, no users have been harmed. Nevertheless, Microsoft regards this
 potential problem with the greatest seriousness and we have worked hard to
 resolve it. Microsoft recommends that customers using File and Printer
 Sharing upgrade to the newer drivers.

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 How do I know if I am affected?

 Only customers who use the File and Printer Sharing option to share their
 files with other users on a network are affected. This option is not
 enabled by default, so unless you have manually enabled it, you are not
 affected by this issue. To determine if File and Printer Sharing is
 enabled, double-click the Network icon in the Control Panel. You will see
 a dialog box similar to one of the following.

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 What are the issues?

 File and Printer Sharing for NetWare Networks

 Microsoft was made aware of an issue with File and Printer Sharing for
 NetWare® Networks which might affect data security for corporate users.

 Only users whose environments meet both of the following conditions can be
 affected:

   1. They configure their machine to share files and printers with other
      users on the network by using File and Printer Sharing for NetWare
      Networks (this option is not turned on by default).
   2. They enable remote administration or install Microsoft Remote
      Registry Services (these options are not turned on by default)

 If your configuration matches that listed above, it is possible for
 another user on the network to gain read-only access to your computer
 after the administrator has logged off the machine, until you restart your
 computer. To correct this problem, Microsoft has issued an updated driver
 for File and Printer Sharing for NetWare Networks. The updated driver
 ensures that only valid administrators have access to the computer’s
 drive.

 File and Printer Sharing for Microsoft Networks (not MSN™: The Microsoft
 Network online service)

 Microsoft has also issued an update for a known problem with File and
 Printer Sharing for Microsoft Networks and a certain UNIX® shareware
 network client (Samba’s SMBCLIENT). The update corrects a problem with
 share-level security documented in the Microsoft Knowledge Base on October
 9th. The update also includes a correction for a similar problem with
 user-level security that Microsoft discovered as part of its internal
 testing of the new driver.

 Customers whose environments meet all of the conditions below might have
 their data susceptible to network or Internet hackers:

   1. They configure their machine to share files and printers with other
      users on the network using File and Printer Sharing for Microsoft
      Networks (this option is not turned on by default).
   2. They share a LAN, Internet, or Dial-Up connection with a UNIX-based
      computer running Samba's SMBCLIENT software.
   3. The network administrator does not disable peer services using System
      Policies.

 Windows 95 allows users of the Samba SMB client to access the drive on
 which sharing is enabled by accepting certain specific networking
 commands. The Samba client is the only known SMB client that sends such
 networking commands. SMBCLIENT users do not automatically have access to
 the Windows 95 drive, and must know the exact steps to send these
 commands.

 The updated driver prevents Windows 95 from accepting these commands,
 preventing SMBCLIENT users from accessing the drive on which sharing is
 enabled. With the updated driver, the SMBCLIENT user will only have access
 to those shared folders that the Windows 95 user has designated.

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 How do I get the updated drivers?

 English versions of both drivers are available for immediate download as
 part of the Windows 95 Service Pack 1.

 Click here for international versions of both drivers, available in
 Danish, Dutch, Finnish, French, German, Italian, Japanese (PC98), Japanese
 (PCAT), Norwegian, Portuguese (Brazilian), Spanish, and Swedish.