Archive for January, 2014

There’s a new version of my PowerShellAccessControl module available in the Script Center Repository. It’s got a lot of new stuff in it, so go check it out. I’m going to just show you some random commands to run (and I’ll post a screenshot or two).

The update brings the ability to audit/modify SACLs (object auditing). It also simplifies getting security descriptors for several objects, including services, printers, WMI namespaces, and more (even file/folder and registry entries). PowerShell v2 is also supported (let me know if you find anything that doesn’t work when using v2). It’s still lacking the functions I’ve been working on to actually save the security descriptors back out. Don’t worry, though, because those are coming. I’m also working on other ways for the module to get its hands on more security descriptors.

For now, though, I think it does a pretty good job of letting you audit your ACLs for almost anything you’d want to (and if it doesn’t directly support the object, you can still use New-AdaptedSecurityDescriptor if you know the SDDL or binary form of the SD). You can also use New-AccessControlEntry to create file, folder, and registry ACEs to use with Get-Acl and Set-Acl. That by itself saves several lines of code.

Anyway, go download the module, then run through some of these demo scripts line by line:

Working with services:

# Must be run as admin b/c of GetSecurityDescriptor WMI method

# Get BITs service SD
$SD = Get-Service bits | Get-SecurityDescriptor

# Check out the default formatting
$SD

# And as a list:
$SD | fl

# Show ACEs (access and audit) for services that start with the letter 'B'
Get-Service b* | Get-AccessControlEntry

# Show auditing ACEs for services that start with the letter 'B'
Get-Service b* | Get-AccessControlEntry -AclType Audit

# Get BITs service SD (again)
$SD = Get-Service bits | Get-SecurityDescriptor

# Give users the ability to Start and Stop it:
$SD.AddAccessRule((New-AccessControlEntry -ServiceAccessRights Start, Stop -Principal Users))
# Audit that
$SD.AddAuditRule((New-AccessControlEntry -ServiceAccessRights Start, Stop -Principal Users -AuditSuccess))

# Look to make sure those entries are there:
$SD | fl
#or
$SD.Access
$SD.Audit

# Since there's no Set-SecurityDescriptor yet, do this if you want to save
# SD (you have to remove -WhatIf to make it permanent)
$Win32SD = $SD | ConvertTo-Win32SecurityDescriptor -ValueOnly  # Use -LegacyWmiObject if you're going to use WMI cmdlets
Get-CimInstance Win32_Service -Filter "Name='bits'" | Invoke-CimMethod -MethodName SetSecurityDescriptor -WhatIf -Arguments @{
    Descriptor = $Win32SD
}

Working with other objects:

# Printers
Get-WmiObject Win32_Printer | Get-SecurityDescriptor

# Printer access ACE:
$ACE = New-AccessControlEntry -PrinterRights ManageDocuments -Principal Users

# Logical share:
Get-CimInstance Win32_LogicalShareSecuritySetting | Get-SecurityDescriptor

# WSMan:
dir wsman: -Recurse | ? { $_.Name -eq "SDDL" } | Get-SecurityDescriptor

# Folder:
get-item c:\windows | Get-SecurityDescriptor
dir c:\windows -Directory | Get-AccessControlEntry -AceNotInherited
dir c:\windows -Directory | Get-AccessControlEntry -IdentityReference Administrators

# WMI namespace:
$SD = Get-CimInstance __SystemSecurity -Namespace root/cimv2 | Get-SecurityDescriptor

# Add an access ACE that also applies to all child namespaces:
$SD.AddAccessRule((New-AccessControlEntry -WmiNamespaceRights RemoteEnable -Principal Users -AppliesTo Object, ChildContainers))

# View the modified ACL:
$SD.Access
 
# Get new SDDL:
$SD.Sddl
 
# Get new binary form:
$SD.GetSecurityDescriptorBinaryForm()

# Remember, WMI namespace SD hasn't been modified for real, just in in-memory instance of SD

Audit all WMI namespace rights:

function Get-ChildNamespace {

    param(
        [string] $Namespace = "root",
        [int] $Level = 1
    )

    # Decrement level (if argument wasn't supplied, you'll only get
    # the direct chidren)
    $Level--

    Get-WmiObject __Namespace -Namespace $Namespace | select -exp name | ForEach-Object {

        [PsCustomObject] @{
            FullName = "$Namespace\$_"
            Name = $_
            Namespace = $Namespace
        }

        # Negative numbers mean recurse forever
        if ($Level) {
            & $MyInvocation.MyCommand -Namespace "$Namespace\$_" -RecurseLevel $Level
        }
    }
}

# Store SDs for all namesapces in $WmiNsSD (gwmi)
$WmiSDs = Get-ChildNamespace -Level -1 | 
    select -exp fullname | 
    % {"root"}{ $_ } | 
    sort | 
    % { Get-WmiObject -EnableAllPrivileges __SystemSecurity -Namespace $_ } | 
    Get-SecurityDescriptor

# Just show with default formatting:
$WmiSDs

# Or show with ACEs expanded as their own objects
$WmiSDs | Get-AccessControlEntry


# Only show ACEs that aren't inherited:
$WmiSDs | Get-AccessControlEntry -AceNotInherited

And here is a screenshot showing the default formatting after calling ‘Get-Service b* | Get-AccessControlEntry’:

Get-Service b* | Get-AccessControlEntry

Get-Service b* | Get-AccessControlEntry

And one after calling ‘Get-Service bits | Get-SecurityDescriptor’

Get-Service | Get-SecurityDescriptor

Get-Service | Get-SecurityDescriptor

There are a lot of examples in the comment based help for the functions, too. If you have any issues/suggestions, please let me know.

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