Active Directory – Decoding UserAccountControl Attribute Values

In Active Directory, When we open properties of an user account, click the Account tab, and then either check or uncheck boxes in the Account options dialog box, numerical values are assigned to the UserAccountControl attribute. This UserAccountControl attribute determines the state of an account in the AD domain: active or locked, Password change at the next logon is enabled or not, if users can change their passwords and other options.

UserAccountControl Attribute in AD

To view user accounts,

1. Click Start –> Programs
2. Open Administrative Tools
3. Click Active Directory Users and Computers
   • Or run dsa.msc from run window
4. Search for a user and right-click and select Properties
5. Click on Account tab

The Account Options section has the following options,

• User must change password at next logon
• User cannot change password
• Password never expires
• Store password using reversible encryption
• Account is disabled
• Smart card is required for interactive logon
• Account is sensitive and cannot be delegated
• User Kerberos DES encryption types for this account
• This account supports Kerberos AES 128 bit encryption
• This account supports Kerberos AES 256 bit encryption
• Do not require Kerberos preauthentication

Each of these user account options is 1 (True) or 0 (False) and are not stored as separate AD attributes, instead the UserAccountControl attribute is used. The flags are cumulative. The total value of all options are stored in the value of UserAccountControl attribute.

To determine the current value of the attribute,

Using PowerShell,

$user = Read-Host "Enter user's logon"
Get-ADuser $user -properties * | Select name, UserAccountControl | ft

Using dsa.msc,

1. dsa.msc from Run window
2. Search for a user and right-click and select Properties
3. Click on Attribute Editor tab
   • If you are missing this tab, Click View in the Active Directory Users and Computers window and select Advanced Features

In this example, the value of the attribute is 0x200 (decimal value is 512).

The following table lists possible flags that can be assigned to an account. Each flag corresponds to a certain UserAccountControl bit, and UserAccountControl value equals the sum of all flags.

UserAccountControl Flag	Hexadecimal Value	Decimal Value
SCRIPT	0x0001	1
ACCOUNTDISABLE	0x0002	2
HOMEDIR_REQUIRED	0x0008	8
LOCKOUT	0x0010	16
PASSWD_NOTREQD	0x0020	32
PASSWD_CANT_CHANGE	0x0040	64
ENCRYPTED_TEXT_PWD_ALLOWED	0x0080	128
TEMP_DUPLICATE_ACCOUNT	0x0100	256
NORMAL_ACCOUNT	0x0200	512
INTERDOMAIN_TRUST_ACCOUNT	0x0800	2048
WORKSTATION_TRUST_ACCOUNT	0x1000	4096
SERVER_TRUST_ACCOUNT	0x2000	8192
DONT_EXPIRE_PASSWORD	0x10000	65536
MNS_LOGON_ACCOUNT	0x20000	131072
SMARTCARD_REQUIRED	0x40000	262144
TRUSTED_FOR_DELEGATION	0x80000	524288
NOT_DELEGATED	0x100000	1048576
USE_DES_KEY_ONLY	0x200000	2097152
DONT_REQ_PREAUTH	0x400000	4194304
PASSWORD_EXPIRED	0x800000	8388608
TRUSTED_TO_AUTH_FOR_DELEGATION	0x1000000	16777216
PARTIAL_SECRETS_ACCOUNT	0x04000000	67108864

The userAccountControl value is calculated as,

NORMAL_ACCOUNT (512) + ACCOUNTDISABLE (2) = 514

NORMAL_ACCOUNT (512) + DONT_EXPIRE_PASSWORD (65536) + ACCOUNTDISABLE (2) = 66050

To list all active users,

Get-ADUser -Properties * -ldapFilter "(useraccountcontrol=512)" | Select UserPrincipalName,userAccountControl | ft

To list all disabled user accounts,

Get-ADUser -Properties * -ldapFilter "(useraccountcontrol=514)" | Select UserPrincipalName,userAccountControl | ft

To list accounts with a non-expiring password,

Get-ADUser -Properties * -ldapFilter "(useraccountcontrol=66048)" | Select UserPrincipalName,userAccountControl | ft

Here are the default UserAccountControl values for the certain objects:

• Typical user: 0x200 (512)
• Domain controller: 0x82000 (532480)
• Workstation/server: 0x1000 (4096)

Decode UserAccountControl Values

To fully decode UserAccountControl bit field we can use this PowerShell script,

Add-Type -TypeDefinition @'
[System.Flags]
public enum UserAccountControl{
	SCRIPT = 1,
	ACCOUNTDISABLE = 2,
	BIT_02 =  4,
	HOMEDIR_REQUIRED = 8,
	LOCKEDOUT = 16,
	PASSWD_NOTREQD = 32,
	PASSWD_CANT_CHANGE = 64,
	ENCRYPTED_TEXT_PWD_ALLOWED = 128,
	TEMP_DUPLICATE_ACCOUNT = 256,
	NORMAL_ACCOUNT = 512,
	BIT_10 = 1024,
	INTERDOMAIN_TRUST_ACCOUNT = 2048,
	WORKSTATION_TRUST_ACCOUNT = 4096,
	SERVER_TRUST_ACCOUNT = 8192,
	BIT_14 = 16384,
	BIT_15 = 32768,
	DONT_EXPIRE_PASSWORD = 65536,
	MNS_LOGON_ACCOUNT = 131072,
	SMARTCARD_REQUIRED = 262144,
	TRUSTED_FOR_DELEGATION = 524288,
	NOT_DELEGATED = 1048576,
	USE_DES_KEY_ONLY = 2097152,
	DONT_REQ_PREAUTH = 4194304,
	PASSWORD_EXPIRED = 8388608,
	TRUSTED_TO_AUTH_FOR_DELEGATION = 16777216,
	PARTIAL_SECRETS_ACCOUNT = 67108864
}
'@

Which can be used like this to decode the bits,

If you want to display all flags that are set in UAC,

Get-AdUser -Filter * -Properties UserAccountControl | select name, @{n='UAC';e={[UserAccountControl]$_.UserAccountControl}}

This script can also be used to determine UserAccountControl value for specific AD accounts,

$user = Read-Host "Enter user's logon"
Get-ADuser $user -properties * | select name,UserPrincipalName, @{n='UAC';e={[UserAccountControl]$_.UserAccountControl}}

Update UserAccoutControl Attribute in AD using PowerShell

To change UserAccountControl attribute in AD using PowerShell, we can use Set-ADUser, Set-ADComputer and Set-ADAccountControl cmdlets,

$user = Read-Host "Enter user's logon"
Set-ADAccountControl -Identity $user –CannotChangePassword:$true -PasswordNeverExpires:$true

or

$user = Read-Host "Enter user's logon"
Set-ADUser -Identity $user –CannotChangePassword:$true -PasswordNeverExpires:$true

Set a specified computer to be trusted for delegation,

$Computer = Read-Host "Enter computer or server name"
Set-ADAccountControl -Identity $Computer -TrustedForDelegation $True

or

$Computer = Read-Host "Enter computer or server name"
Set-ADComputer -Identity $Computer -TrustedForDelegation $True

The user account attribute can also be updated using the Set-ADUser cmdlet. In this below example, I’m enabling user account,

$user = Read-Host "Enter user's logon"
Set-ADUser $user -Replace @{UserAccountControl = 512}

Hope this post helped you get a better understanding of the UserAccountControl attribute.

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