seikaikyo/hunting-for-dcsync-attacks
external/anthropic-cybersecurity-skills/skills/hunting-for-dcsync-attacks/SKILL.md
Detect DCSync attacks by analyzing Windows Event ID 4662 for unauthorized DS-Replication-Get-Changes requests from non-domain-controller accounts.
$ install --global
skillsauthnpx skillsauth add seikaikyo/dash-skills hunting-for-dcsync-attacksInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
Security Scan Results
3 of 9 scanners reported clean
Some scanners were skipped, did not run, or reported a non-clean status. Review each row below.
3
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9
Scanners in report
Clean
TrivyContainer and dependency vulnerability scanner
95%
Clean
SemgrepStatic code analysis for vulnerabilities
95%
Clean
mcp-scan (Snyk)Model Context Protocol security validation
95%
Skipped
Snyk (dep)Open source security scanning
50%
Skipped
Socket.devSupply chain security analysis
50%
Skipped
VirusTotalMulti-engine malware detection
50%
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CrowdStrikeAdvanced threat intelligence
50%
Skipped
OSV-ScannerOpen Source Vulnerability database check
50%
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OWASP Dep-Check
50%
Last scanned: Jun 6, 2026, 5:36 AM177.9s3 files scanned
SKILL.md
- name:
- hunting-for-dcsync-attacks
- description:
- Detect DCSync attacks by analyzing Windows Event ID 4662 for unauthorized
- domain:
- cybersecurity
- subdomain:
- threat-hunting
- version:
- 1.0
- author:
- mahipal
- license:
- Apache-2.0
Hunting for DCSync Attacks
When to Use
- When hunting for DCSync credential theft (MITRE ATT&CK T1003.006)
- After detecting Mimikatz or similar tools in the environment
- During incident response involving Active Directory compromise
- When monitoring for unauthorized domain replication requests
- During purple team exercises testing AD attack detection
Prerequisites
- Windows Security Event Log forwarding enabled (Event ID 4662)
- Audit Directory Service Access enabled via Group Policy
- Domain Computers SACL configured on Domain Object for machine account detection
- SIEM with Windows event data ingested (Splunk, Elastic, Sentinel)
- Knowledge of legitimate domain controller accounts and replication partners
Workflow
- Enable Auditing: Ensure Audit Directory Service Access is enabled on domain controllers.
- Collect Events: Gather Windows Event ID 4662 with AccessMask 0x100 (Control Access).
- Filter Replication GUIDs: Search for DS-Replication-Get-Changes and DS-Replication-Get-Changes-All.
- Identify Non-DC Sources: Flag events where SubjectUserName is not a domain controller machine account.
- Correlate with Network: Cross-reference source IPs against known DC addresses.
- Validate Findings: Exclude legitimate replication tools (Azure AD Connect, SCCM).
- Respond: Disable compromised accounts, reset krbtgt, investigate lateral movement.
Key Concepts
| Concept | Description | |---------|-------------| | DCSync | Technique abusing AD replication protocol to extract password hashes | | Event ID 4662 | Directory Service Access audit event | | DS-Replication-Get-Changes | GUID 1131f6aa-9c07-11d1-f79f-00c04fc2dcd2 | | DS-Replication-Get-Changes-All | GUID 1131f6ad-9c07-11d1-f79f-00c04fc2dcd2 | | AccessMask 0x100 | Control Access right indicating extended rights verification | | T1003.006 | OS Credential Dumping: DCSync |
Tools & Systems
| Tool | Purpose | |------|---------| | Windows Event Viewer | Direct event log analysis | | Splunk | SIEM correlation of Event 4662 | | Elastic Security | Detection rules for DCSync patterns | | Mimikatz lsadump::dcsync | Attack tool used to perform DCSync | | Impacket secretsdump.py | Python-based DCSync implementation | | BloodHound | Identify accounts with replication rights |
Output Format
Hunt ID: TH-DCSYNC-[DATE]-[SEQ]
Technique: T1003.006
Domain Controller: [DC hostname]
Subject Account: [Account performing replication]
Source IP: [Non-DC IP address]
GUID Accessed: [Replication GUID]
Risk Level: [Critical/High/Medium/Low]
Recommended Action: [Disable account, reset krbtgt, investigate]
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