Hiding In Active Directory: Techniques And Detection

Did you know you can hide in Active Directory—even from Domain Admins? Here’s how:

1️⃣ Make the account unsearchable

Apply a Deny Full Control ACL for “Everyone” on the target account to prevent visibility or modification.

2️⃣ Prevent group membership visibility

Use the Primary Group feature instead of traditional group memberships. This ensures the group membership isn’t exposed in standard lookups.

3️⃣ Hide the account in unexpected locations

Place the account in a misleading Organizational Unit (OU) and apply Deny List Content ACLs on the final OU to obscure it further.

Detection Tips:

Monitor for primary group changes.
Look for suspicious ACL modifications (especially Deny).
Check AD object-level changes in Event logs.
Use SAM-R protocol for enumeration (depending on configuration).

Tools:

AD Probe tool: https://lnkd.in/e7QxuJQi
Semperis utility for hidden objects: https://www.semperis.com/blog/find-hidden-active-directory-objects/

Commands for Detection:

PowerShell:

Get-ADUser -Filter * -Properties MemberOf | Where-Object { $_.MemberOf -eq $null }

Windows Command
[cmd]
dsquery user -limit 0
[/cmd]

Linux (using ldapsearch):

ldapsearch -x -h <domain-controller> -b "dc=example,dc=com" "(objectClass=user)"

What Undercode Say:

Active Directory (AD) is a critical component of enterprise IT infrastructure, and its security is paramount. The techniques discussed in this article highlight how attackers can exploit AD misconfigurations to hide accounts and maintain persistence. To mitigate these risks, administrators must regularly scan for misconfigurations, monitor event logs, and use tools like AD Probe or Semperis utilities.

In addition to the commands provided, here are more Linux and Windows commands to enhance your AD security posture:
– Linux:


<h1>Check for open LDAP ports</h1>

nmap -p 389,636 <domain-controller>

<h1>Enumerate users with ldapsearch</h1>

ldapsearch -x -h <domain-controller> -b "dc=example,dc=com" "(objectClass=user)"

– Windows:


<h1>Check for hidden accounts</h1>

Get-ADUser -Filter {adminCount -eq 1} -Properties adminCount

<h1>Monitor ACL changes</h1>

Get-EventLog -LogName Security -InstanceId 4662

Regularly auditing AD configurations and staying updated on the latest security practices is crucial. For further reading, explore the following resources:
– SpecterOps: Ace up the Sleeve
– Microsoft Defender for Identity

By implementing these practices and tools, you can significantly reduce the risk of hidden accounts and ensure a more secure Active Directory environment.

References:

initially reported by: https://www.linkedin.com/posts/horizon-secured_windows-cybersecurity-activedirectory-activity-7299722254081282048-8Bky – Hackers Feeds
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