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2.2.18 Ensure 'Create symbolic links' is set to 'Administrators, NT VIRTUAL MACHINE\Virtual Machines' (MS only)

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Information

This policy setting determines which users can create symbolic links. In Windows Vista, existing NTFS file system objects, such as files and folders, can be accessed by referring to a new kind of file system object called a symbolic link. A symbolic link is a pointer (much like a shortcut or .lnk file) to another file system object, which can be a file, folder, shortcut or another symbolic link. The difference between a shortcut and a symbolic link is that a shortcut only works from within the Windows shell. To other programs and applications, shortcuts are just another file, whereas with symbolic links, the concept of a shortcut is implemented as a feature of the NTFS file system.

Symbolic links can potentially expose security vulnerabilities in applications that are not designed to use them. For this reason, the privilege for creating symbolic links should only be assigned to trusted users. By default, only Administrators can create symbolic links.

The recommended state for this setting on Member Servers is: Administrators and (when the Hyper-V Role is installed) NT VIRTUAL MACHINE\Virtual Machines.

Users who have the Create symbolic links user right could inadvertently or maliciously expose your system to symbolic link attacks. Symbolic link attacks can be used to change the permissions on a file, to corrupt data, to destroy data, or as a denial-of-service attack.

Solution

To implement the recommended configuration state, configure the following UI path to Administrators and (when the Hyper-V Role is installed) NT VIRTUAL MACHINE\Virtual Machines :

Computer Configuration\Policies\Windows Settings\Security Settings\Local Policies\User Rights Assignment\Create symbolic links

Impact:

In most cases there will be no impact because this is the default configuration. However, on Windows Servers with the Hyper-V server role installed, this user right should also be granted to the special group Virtual Machines - otherwise you will not be able to create new virtual machines.

See Also

https://workbench.cisecurity.org/benchmarks/25708

Item Details

Category: ACCESS CONTROL, AUDIT AND ACCOUNTABILITY

References: 800-53|AC-2, 800-53|AC-3, 800-53|AC-6, 800-53|AC-6(1), 800-53|AC-6(7), 800-53|AU-9(4)

Plugin: Windows

Control ID: 76b9cdee8287abff8449dc79e0bb9e16d998ea1c30adfff18b2e45abda075003