Microsoft KB Archive/825137

= Server for NFS clears or does not permit you to set the Setuid bit or the Setgid bit =

Article ID: 825137

Article Last Modified on 10/25/2005

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APPLIES TO


 * Microsoft Windows Services for UNIX 3.0 Standard Edition
 * Microsoft Windows Services for Unix 2.3

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SYMPTOMS
For files and directories that are group writable or group executable or world writable or world executable, you may experience the following symptoms:
 * If you set either the setuid bit or the setgid bit, when you make the file or directory to be group writable or group executable or world writable or world executable, the bit is cleared.
 * If the file or directory is already group writable or group executable or world writable or world executable, you cannot set the setuid and setgid bits.



RESOLUTION
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.    Date         Time   Version            Size    File name --  01-Aug-2003  06:37  7.0.1701.20        23,040  Dsctrs.dll 01-Aug-2003 06:37  7.0.1701.20        25,088  Nfsonly.exe 01-Aug-2003 06:37  7.0.1701.20        67,072  Nfssh.dll 01-Aug-2003 06:37  7.0.1701.20        88,576  Nfsshare.exe 01-Aug-2003 06:37  7.0.1701.20       143,872  Nfsshex.dll 01-Aug-2003 06:37  7.0.1701.20       114,176  Nfssprop.dll 01-Aug-2003 06:37  7.0.1701.20        97,280  Nfssvc.exe 01-Aug-2003 06:37  7.0.1701.20       325,312  Nfssvr.sys 01-Aug-2003 06:37  7.0.1701.20       323,488  Nfssvrn4.sys 01-Aug-2003 06:37  7.0.1701.20        42,624  Portmap.sys 01-Aug-2003 06:37  7.0.1701.20        73,056  Rpcxdr.sys



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section of this article.



MORE INFORMATION
As a result of the Microsoft Trustworthy Computing Initiative, Server for NFS has been changed to fix a known security issue in UNIX. Server for NFS masks out certain mode bits to fix an issue that occurs when a file or directory has the setuid bit or the setgid bit behavior enabled and when the file or the directory is either group writable or world writable.

The exploitation of the situation is when an intruder overwrites the binary with a Trojan horse and then executes the binary. The binary runs with the rights of the owner, instead of running as the intruder.

Some customers may find this security update problematic because the security update deviates from UNIX behavior, although this behavior is not specified in the Network File System (NFS) RFC.

The bit masking occurs only if the file or directory has both of the following characteristics:
 * One or both of the following bits is set:setgid or setuid.
 * Group writable or group executable or world writable or world executable.

This hotfix creates the following registry value:

This registry value controls whether the setuid bit and the setgid bit are masked for security reasons. Settings may be as follows:
 * The default data for this registry value is 1.
 * A value of 1 causes the bits to be masked out for security reasons.
 * A value of 0 causes the standard UNIX behavior.

This hotfix also turns off bit masking for the setuid bit and the setgid bit for directories because directories cannot be executed. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

Keywords: kbbug kbfix kbqfe kbhotfixserver KB825137

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