Active Directory Hardening: Best Practices and Implementation

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2025-02-09

Active Directory (AD) hardening is a critical process to protect an organization’s AD infrastructure from unauthorized access and cyber threats. Below are some best practices along with practical commands and codes to implement these strategies effectively.

1. Disabling NTLMv1

NTLMv1 is an outdated authentication protocol that is vulnerable to various attacks. Disabling it enhances security.

Command:

Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Lsa" -Name "LmCompatibilityLevel" -Value 5

2. Removing SMBv1

SMBv1 is another outdated protocol that is susceptible to attacks like EternalBlue. Removing it is essential.

Command:

Disable-WindowsOptionalFeature -Online -FeatureName SMB1Protocol

3. Enforcing LDAP Signing

LDAP signing ensures that LDAP traffic is signed and protected from tampering.

Command:

Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\NTDS\Parameters" -Name "LDAPServerIntegrity" -Value 2

4. Enforcing AES for Kerberos

Using AES for Kerberos encryption provides stronger security compared to older encryption types.

Command:

Set-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\Kerberos\Parameters" -Name "SupportedEncryptionTypes" -Value 0x18

5. Enforcing LDAP Channel Binding

LDAP channel binding helps prevent relay attacks by binding the LDAP session to the TLS channel.

Command:

Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\NTDS\Parameters" -Name "LdapEnforceChannelBinding" -Value 2

6. Enforcing SMB Signing

SMB signing ensures that SMB traffic is signed and protected from tampering.

Command:

Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters" -Name "RequireSecuritySignature" -Value 1

7. Implementing Least Privilege

Implementing the principle of least privilege ensures that users and services have only the permissions they need.

Command:


<h1>Example: Restricting user permissions</h1>

Set-ADUser -Identity "username" -Enabled $false

What Undercode Say

Active Directory hardening is a multifaceted approach that involves disabling outdated protocols, enforcing secure communication, and implementing the principle of least privilege. By following these best practices, organizations can significantly enhance their AD security posture.

  1. Disabling NTLMv1: This protocol is outdated and vulnerable. Disabling it is a straightforward yet effective measure.
  2. Removing SMBv1: SMBv1 is a known vulnerability. Removing it mitigates risks associated with exploits like EternalBlue.
  3. Enforcing LDAP Signing: Ensures that LDAP traffic is signed, protecting it from tampering.
  4. Enforcing AES for Kerberos: AES provides stronger encryption, making it harder for attackers to compromise Kerberos tickets.
  5. Enforcing LDAP Channel Binding: Prevents relay attacks by binding the LDAP session to the TLS channel.
  6. Enforcing SMB Signing: Protects SMB traffic from tampering by ensuring it is signed.
  7. Implementing Least Privilege: Reduces the attack surface by ensuring users and services have only the permissions they need.

Additional Commands for Enhanced Security:

  • Audit Policy Configuration: 
    auditpol /set /category:"Account Logon" /success:enable /failure:enable

  • Firewall Configuration:

    New-NetFirewallRule -DisplayName "Block SMBv1" -Direction Inbound -Action Block -Protocol TCP -LocalPort 445

  • Group Policy Update:

    gpupdate /force

  • Check AD Replication Status:

    repadmin /showrepl

  • Monitor AD Changes:

    Get-EventLog -LogName Security -InstanceId 4662

Useful URLs:

By implementing these strategies and commands, organizations can create a more secure and resilient Active Directory environment. Regular audits and updates are essential to maintain this security posture.

References:

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