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NTFS vs. CHMODs (Property/Permissions) (Read 7927 times)
Captain John

NTFS vs. CHMODs (Property/Permissions)
Sep 24th, 2007 at 10:02pm
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Since CHMOD is exclusively a feature of *nix based systems, users on Windows platform will not have the option of CHMODding any files. This is perfectly normal and will not prevent your YaBB from working correctly. How to set permissions on a Windows Server If you are running on a Windows host with IIS (Most hosted services running on windows will use IIS), you might need to set the NTFS and IIS permissions to make things operate properly.

Note that you might not be able to set these permissions yourself, or you might only be able to set either the IIS or the NTFS permissions, so you will often have to ask your host to do this for you.

IIS Permissions These permissions are set from the IIS service manager. Setting these permissions merely adds extra security to your site, but that does not mean they should be skipped, but usually will allow YaBB to run as written to by Default.

NTFS Permissions These permissions sets the read/write rights to your directories and files. These must be set correctly, or YaBB won't be able to read from or write to the files it is supposed to, making your forum unusable. On a defualt server setup, these permissions should be granted to the Anonymous Internet User (IUSR_servername), but which user IIS uses the permissions from can be changed in the IIS manager. The NTFS permissions is set from the windows explorer interface, and the settings listed here assume two things: - Permissions are set to be inherited by child directories and files - Only the neccessarry permissions are specified in the table, not permissions that windows grant automatically when setting the specified permission. For example, checking the 'Modify' Permission causes windows to automatically check 'Read & Execute', 'List Folder Contents', 'Read', and 'Write'. Tjis is how it is supposed to be. Don't try to uncheck the others just because modify is the only thing listed in the table below (If you try, you will find that unchecking any of them also unchecks 'modify', so it should be pretty obvious which permissions that actually needs to be checked to allow for the listed permission).

Directory NTFS Permissions IIS Permission

cgi-bin/yabb2 Read & Execute Read, No write, No directory browsing, Scripts only execute permission

cgi-bin/yabb2/Admin Read & Execute No read, No write, No directory browsing, No execute permission

cgi-bin/yabb2/Boards Modify No read, No write, No directory browsing, No execute permission

cgi-bin/yabb2/Help Modify No read, No write, No directory browsing, No execute permission

cgi-bin/yabb2/Languages Read & Execute No read, No write, No directory browsing, No execute permission

cgi-bin/yabb2/Members Modify Read, Write, No directory browsing, No execute permission

cgi-bin/yabb2/Messages Modify Read, Write, No directory browsing, No execute permission

cgi-bin/yabb2/Modules Read & Execute No read, No write, No directory browsing, No execute permission

cgi-bin/yabb2/Sources Read & Execute No read, No write, No directory browsing, No execute permission

cgi-bin/yabb2/Templates Modify No read, No write, No directory browsing, No execute permission

cgi-bin/yabb2/Variables Modify No read, No write, No directory browsing, No execute permission

public_html/yabbfiles Read & Execute Read, No write, No directory browsing, No execute permission

public_html/yabbfiles/Attachements Modify Read, No write, No directory browsing, No execute permission

public_html/yabbfiles/Templates Modify Read, No write, No directory browsing, No execute permission

public_html/yabbfiles/[All other dirs] Read & Execute Read, No write, No directory browsing, No execute permission

checked by Jon B - June 27 2009
« Last Edit: Jun 27th, 2009 at 5:36pm by »  
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Captain John

Re: NTFS vs. CHMODs (Property/Permissions)
Reply #1 - Feb 26th, 2010 at 7:42pm
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Understanding Windows NTFS Permissions

Even though Windows permissions have been around for a long time, I still run into seasoned network administrators that aren’t aware of the new changes that came with Windows 2000 so long ago. When Microsoft released Windows 2000, they released a new version of NTFS, which was versioned 5. The new NTFS permissions were essentially the same logical control as the older version that was available in Windows NT, however, there were some radical and essential changes that occurred to control how the permissions were inherited and configured for each file and folder. Since NTFS permissions are available on every file, folder, Registry key, printer, and Active Directory object, it is important to understand the new methods and features that are available once you have Windows 2000, Windows XP, Vista or Windows 2003 Server installed to control resources.

Standard Permissions

Standard permissions are those permissions that control a broad range of detailed permissions. The most popular and infamous standard permission is Full Control. This is what everyone wants, but in reality very few should get. Full Control allows the user that is granted this suite of permissions to do virtually anything to the object the permissions are associated with. The other standard permissions include the following:


    Read & Execute

Folders have the same standard permissions as files, except there is one additional standard permission “List Folder Contents.”

When you look at Registry keys, printers, and Active Directory objects, there is a totally different set of standard permissions for these objects. The security tab of each object will list the standard permissions.

Advanced Permissions

Advanced permissions are the detailed permissions that are grouped together to create the standard permissions. Since advanced permissions are used in combinations to create the standard permissions, there are more of them overall. For a file, here is a list of the advanced permissions:

    Full Control
    Traverse Folder/Execute File
    List Folder/Read Data
    Read Attributes
    Read Extended Attributes
    Create Files/Write Data
    Create Folders/Append Data
    Write Attributes
    Write Extended Attributes
    Read Permissions
    Change Permissions
    Take Ownership

For example, the specific advanced permissions that are used to create the Read standard permission include:

    List Folder/Read Data
    Read Attributes
    Read Extended Attributes
    Read Permissions

When you evaluate the advanced permissions for a folder, they are identical to those of a file. However, when you investigate the advanced permissions of a printer or Registry key, they are completely different. If you want to see the power and control that NTFS 5.0 provides for access control, it is best to investigate the permissions of an OU within Active Directory. Upon first glance, I calculate that you have over 10,000 individual advanced permissions that you can set for an OU.

Inherited vs. Explicit Permissions

There are two variations of permissions that you will see for any one entry (user, computer, or group) listed on the access control list (ACL). If we look at the root drive, C:, you can add or modify the permissions for any entry on the ACL. If you create a new folder under C:, say a new folder named Data (C:\Data), you won’t be able to modify the permissions for any existing entries. This is because the permissions from C: inherit down to all subfolders and files automatically. If you don’t want the permissions from C: to inherit down the C:\Data, but still want them to inherit down to other subfolders below C:, you would configure the C:\Data folder to stop inheriting by removing the check from the “Inherit from parent the permission entries that apply to child objects. Include these with entries explicitly defined here”.  At any level within the resource structure, you can always add new entries to the ACL. These entries, specifically for the target resource, are called explicit permissions, since they are configured directly on the resource. If the default inheritance is enabled for subfolders and files, these explicit permissions will inherit down to subsequent resources, like the original permissions did from C:\ down to C:\Data. It is easy to tell the difference between inherited permissions and explicit permissions, by the check mark on the permissions for the entry. If the check is not grayed out, the permissions are explicit.

Allow vs. Deny Permissions

When establishing permissions, you need to specify whether the entry should have access (Allow) or not (Deny) to the resource. The Local Security Authority (LSASS) then controls the access to the resource, based on the security ID (SID) that you placed on the ACL to the SID placed on the security token that is given to the user at logon. If the SID associated with the user is on the ACL, the LSASS must determine whether the access is set to Allow or Deny. The Allow and Deny permissions inherit down through the structure as described in the section above on inheritance.

You will get warnings from the ACL editor when you create Deny entries

    Deny entries on the ACL will cause the system to warn you about the limited access you are providing

It is not common to configure resources with Deny permissions, because of the nature of how permissions are evaluated. It is more common to exclude the user or group from the ACL instead of configuring them to have explicit Deny permissions. The fact that the user or group SID is not on the ACL will have the same result of “No Access” to the resource, without needing to configure any special entries on the ACL. It is only in the rare instance that a user or group should be explicitly denied access that you configure Deny permissions. Denial of access to resources by omission from the ACL is easier to troubleshoot, manage, and configure.
Permission Precedence

I hear all of the time from students and other network administrators that Deny permissions take precedence over Allow permissions. Unfortunately, this is not always the case. To prove my point, let’s look at a scenario that you too can create to prove that Deny permissions don’t always take precedence over Allow permissions.

In our scenario, we are going to look at a folder, C:\Data\HR, which contains both public and private files. We have allowed the C:\Data\HR folder to inherit the permissions from C:\Data, which includes just basic permissions from the root folder. We have also included the HR group on the ACL, giving the Group Allow-Read & Execute permissions. The final explicit entry on the ACL is for the non-HR group, which is given Deny-Full Control.

Below the HR folder are two files: Public.doc and Private.doc. The Public folder just allows for normal permission inheritance, so there are no special permissions added to the ACL. However, the private file has some explicit permissions added to the ACL. Since the Executive group needs to be able to read the contents of the private folder, this group is added explicitly with the Allow-Read & Execute permission. The result of this configuration is shown in Figure 5, which clearly shows that the Allow permission for the Executive group has a higher precedence than the Deny permission associated with the non-HR group. Since every executive is included in both groups, you can see that here is a case where Allow permissions have precedence over Deny permissions.

     Allow permissions can have precedence over Deny permissions

The scenario proves that there is a hierarchy of permissions for NTFS 5.0 resources. The hierarchy of precedence for the permissions can be summarized as follows, with the higher precedence permissions listed at the top of the list:

    Explicit Deny
    Explicit Allow
    Inherited Deny
    Inherited Allow


Permissions are almost the same from Windows NT’s NTFS 4.0 to Windows 2000/XP/2003’s NTFS 5.0. One of the main differences is the way that permissions inherit down through the structure with inherited and explicit permissions. It used to be that, if there was a Deny permission on the ACL, it was always evaluated first, then the Allow permissions would follow. Now, the permission hierarchy must be evaluated considering not only the Deny vs. Allow, but whether the permission is explicitly set or inherited down from a parent resource.

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Captain John

Re: NTFS vs. CHMODs (Property/Permissions)
Reply #2 - Feb 27th, 2010 at 12:34am
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Setting NFTS Folder/File Permissions
Right clicking on folders and files is the usual way.  Click on Properties - Security Tab

This is from Vista
NTFS Permissions
Full control Users can see the contents of a file or folder, change existing files and folders, create new files and folders, and run programs in the folder.
Modify Users can change existing files and folders but cannot create new ones
Read & execute Users can see the contents of existing files and folders and can run programs in the folder
Read Users can see the contents of a folder and open files and folders.
Write Users can create new files and folders and make changes to existing files and folders.

To apply permissions to a file or folder
Right-click the file or folder, and then click Properties.

Click the Security tab, and then click Edit.

Do one of the following:

To set permissions for a user that is not listed under Group or user names, click Add, type the name of the user or group, click OK, select the permissions, and then click OK.

   Besides the Security Tab, Unblock on the front page of that Properties window.
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