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Introduction
In the latest HackTheBox VulnLab release, Redelegate challenges cybersecurity professionals to exploit Active Directory delegation misconfigurations, ultimately gaining domain control by abusing SeEnableDelegationPrivilege. This article breaks down the attack path, delegation types, and practical exploitation techniques.
Learning Objectives
- Understand Kerberos delegation (constrained/unconstrained) and its risks.
- Exploit misconfigured delegation privileges to escalate to Domain Admin.
- Apply defensive strategies to audit and secure delegation in AD environments.
1. Enumerating Delegation Configurations
Command (PowerShell):
Get-ADComputer -Filter {msDS-AllowedToDelegateTo -ne "$null"} -Properties msDS-AllowedToDelegateTo
What It Does:
Lists computers configured for constrained delegation. The `msDS-AllowedToDelegateTo` property reveals which services a machine can delegate credentials to.
Steps:
- Run the command in a domain-joined PowerShell session.
2. Identify targets with excessive delegation rights.
- Note the SPNs (Service Principal Names) allowed for delegation.
2. Abusing Unconstrained Delegation
Command (Mimikatz):
sekurlsa::tickets /export
What It Does:
Exports Kerberos tickets stored in memory, including those from users who authenticated to a machine with unconstrained delegation.
Steps:
- Compromise a server with unconstrained delegation (e.g., via
SeEnableDelegationPrivilege). - Use Mimikatz to dump tickets and steal high-privilege TGTs (Ticket-Granting Tickets).
- Pass the ticket to impersonate a Domain Admin.
3. Exploiting Constrained Delegation
Tool: Rubeus
Rubeus.exe s4u /user:COMPUTER$ /rc4:<NTLM_HASH> /impersonateuser:DOMAIN_ADMIN /msdsspn:cifs/TARGET_SERVER /ptt
What It Does:
Requests a service ticket for a target SPN (e.g., CIFS) while impersonating a privileged user.
Steps:
- Extract the computer account’s NTLM hash (e.g., via DCSync or LSASS dump).
- Replace `DOMAIN_ADMIN` and `TARGET_SERVER` with the target’s details.
3. Inject the ticket using `/ptt` (Pass-the-Ticket).
4. Defensive Audit with BloodHound
Query:
MATCH (c:Computer {unconstraineddelegation: true}) RETURN c
What It Does:
Identifies unconstrained delegation misconfigurations in BloodHound.
Steps:
1. Ingest AD data into BloodHound.
2. Run the query to flag risky systems.
3. Review and disable unnecessary delegation.
5. Mitigation: Restricting Delegation
GPO Configuration:
- Navigate to:
`Computer Configuration > Policies > Windows Settings > Security Settings > Local Policies > User Rights Assignment` - Revoke `SeEnableDelegationPrivilege` from non-administrative accounts.
Why It Matters:
Limiting delegation rights reduces the attack surface for Kerberos-based exploits.
What Undercode Say
- Key Takeaway 1: Delegation misconfigurations are a common pivot point for lateral movement. Regularly audit `msDS-AllowedToDelegateTo` and unconstrained delegation settings.
- Key Takeaway 2: Tools like Rubeus and BloodHound streamline both exploitation and defense, emphasizing the need for proactive monitoring.
Analysis:
Active Directory delegation is a double-edged sword—essential for functionality but dangerous if misconfigured. The rise in delegation-based attacks underscores the need for least-privilege principles and continuous AD hygiene.
Prediction
As cloud/hybrid environments adopt Kerberos delegation, attackers will increasingly target misconfigured service accounts. Future AD breaches may leverage AI-driven tools to automate delegation discovery, making manual audits obsolete.
Final Word:
Mastering delegation exploitation and mitigation is critical for both red and blue teams. Test these techniques in labs like HTB’s Redelegate to stay ahead in the AD security game.
IT/Security Reporter URL:
Reported By: 0xdf Htb – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
