Rubeus: Kerberos Exploitation for Penetration Testers

 Rubeus

Rubeus is a powerful post-exploitation tool designed to abuse Kerberos in Windows Active Directory (AD) environments. It’s widely used by penetration testers and red teamers to manipulate authentication mechanisms, extract credentials, and move laterally across compromised networks.

What Is Kerberos?

Kerberos is a network authentication protocol used in AD environments. It uses tickets to allow nodes to prove their identity securely. Rubeus interacts with these tickets to perform various attacks.

Key Capabilities of Rubeus

1. Kerberoasting

• Extracts service account hashes from service tickets (TGS).
• These hashes can be cracked offline to reveal plaintext passwords.

2. Ticket Harvesting

• Dumps Kerberos tickets from memory (e.g., using sekurlsa::tickets via Mimikatz).
• Useful for replay or pass-the-ticket attacks.

3. Pass-the-Ticket

• Injects stolen Kerberos tickets into memory to impersonate users.
• Enables lateral movement without needing passwords.

4. Overpass-the-Hash

• Uses NTLM hashes to request Kerberos tickets.
• Bridges NTLM and Kerberos authentication methods.

5. Golden Ticket Attack

• Creates forged TGTs using the KRBTGT account hash.
• Grants unrestricted access to the domain.

6. Silver Ticket Attack

• Creates forged service tickets (TGS) for specific services.
• Less detectable than Golden Tickets.

7. AS-REP Roasting

• Targets accounts that don’t require pre-authentication.
• Extracts encrypted data that can be cracked offline.

8. Ticket Renewal and Request

• Requests new tickets or renews existing ones.
• Useful for maintaining persistence.

Why Rubeus Is Valuable

• Written in C#, making it easy to compile and modify.
• It can be executed in memory to evade antivirus detection.
• Integrates well with other tools like Mimikatz and Cobalt Strike.

Ethical Use

Rubeus should only be used in environments where you have explicit permission to test. Unauthorized use is illegal and unethical.