Anthropic-Cybersecurity-Skills/skills/detecting-golden-ticket-attacks-in-kerberos-logs/SKILL.md

name, description, domain, subdomain, tags, version, author, license, nist_csf, mitre_attack

name	description	domain	subdomain	tags	version	author	license	nist_csf	mitre_attack
detecting-golden-ticket-attacks-in-kerberos-logs	Detect Golden Ticket attacks in Active Directory using Splunk and KQL queries against domain controller event logs, looking for Kerberos TGT anomalies such as mismatched encryption types, impossible ticket lifetimes, non-existent accounts, and forged PAC signatures. Use when hunting for Kerberos ticket forgery or krbtgt-based persistence (MITRE T1558.001) in AD environments.	cybersecurity	threat-hunting	threat-hunting golden-ticket kerberos active-directory mitre-t1558-001 credential-abuse	1.0	mahipal	Apache-2.0	DE.CM-01 DE.AE-02 DE.AE-07 ID.RA-05	T1046 T1057 T1082 T1083 T1003

Detecting Golden Ticket Attacks in Kerberos Logs

When to Use

• When KRBTGT account hash may have been compromised via DCSync or NTDS.dit extraction
• When hunting for forged Kerberos tickets used for persistent domain access
• After incident response reveals credential theft at the domain level
• When investigating impossible logon patterns (users logging in from multiple locations simultaneously)
• During post-breach assessment to determine if Golden Tickets are in use

Prerequisites

• Windows Security Event IDs 4768, 4769, 4771 on domain controllers
• Kerberos policy configuration knowledge (max ticket lifetime, encryption types)
• Domain controller audit policy enabling Kerberos Service Ticket Operations
• SIEM with ability to correlate Kerberos events across multiple DCs

Workflow

1. Monitor TGT Requests (Event 4768): Track Kerberos authentication service requests. Golden Tickets bypass the AS-REQ/AS-REP exchange entirely, so the absence of 4768 before 4769 is suspicious.
2. Detect Encryption Type Anomalies: Golden Tickets often use RC4 (0x17) encryption. If your domain enforces AES (0x12), any RC4 TGT is a red flag. Monitor TicketEncryptionType in Event 4769.
3. Check Ticket Lifetime Anomalies: Default Kerberos TGT lifetime is 10 hours with 7-day renewal. Golden Tickets can be forged with 10-year lifetimes. Detect tickets with durations exceeding policy.
4. Hunt for Non-Existent SIDs: Golden Tickets can include arbitrary SIDs (including non-existent accounts or groups). Correlate TGS requests against known AD SID inventory.
5. Detect TGS Without Prior TGT: When a service ticket (4769) appears without a preceding TGT request (4768) from the same IP/account, this may indicate a pre-existing Golden Ticket.
6. Monitor KRBTGT Password Age: Track when KRBTGT was last reset. If KRBTGT hash hasn't changed since a known compromise, Golden Tickets from that period remain valid.
7. Validate PAC Signatures: With KB5008380+ and PAC validation enforcement, domain controllers reject forged PACs. Monitor for Kerberos failures indicating PAC validation errors.

Detection Queries

Splunk -- RC4 Encryption in Kerberos TGS

index=wineventlog EventCode=4769
| where TicketEncryptionType="0x17"
| where ServiceName!="krbtgt"
| stats count by TargetUserName ServiceName IpAddress TicketEncryptionType Computer
| where count > 5
| sort -count

Splunk -- TGS Without Prior TGT

index=wineventlog (EventCode=4768 OR EventCode=4769)
| stats earliest(_time) as first_tgt by TargetUserName IpAddress EventCode
| eventstats earliest(eval(if(EventCode=4768, first_tgt, null()))) as tgt_time by TargetUserName IpAddress
| where EventCode=4769 AND (isnull(tgt_time) OR first_tgt < tgt_time)
| table TargetUserName IpAddress first_tgt tgt_time

KQL -- Golden Ticket Indicators

SecurityEvent
| where EventID == 4769
| where TicketEncryptionType == "0x17"
| where ServiceName != "krbtgt"
| summarize Count=count() by TargetUserName, IpAddress, ServiceName
| where Count > 5

Common Scenarios

1. Post-DCSync Golden Ticket: After extracting KRBTGT hash, attacker forges TGT with Domain Admin SID, valid for months until KRBTGT is rotated twice.
2. RC4 Downgrade: Golden Ticket forged with RC4 encryption in an AES-only environment, detectable by encryption type mismatch.
3. Cross-Domain Golden Ticket: Forged inter-realm TGT used to pivot between AD domains/forests.
4. Persistence After Remediation: Golden Tickets surviving password resets because KRBTGT was only rotated once (both current and previous hashes are valid).

Output Format

Hunt ID: TH-GOLDEN-[DATE]-[SEQ]
Suspected Account: [Account using forged ticket]
Source IP: [Client IP]
Target Service: [SPN accessed]
Encryption Type: [RC4/AES128/AES256]
Anomaly: [No prior TGT/RC4 in AES environment/Extended lifetime]
KRBTGT Last Reset: [Date]
Risk Level: [Critical]