Investigate DCSync attacks, which abuse Active Directory replication to steal password hashes. Use audit events and network traffic to identify suspicious replication requests, examine their sources, and check for subsequent credential misuse.
Detect DCSync attacks (MITRE T1003.006) where adversaries abuse Active Directory replication privileges to extract password hashes, by auditing Event ID 4662 for the DS-Replication-Get-Changes GUIDs and flagging non-domain-controller accounts issuing DsGetNCChanges RPC calls. Use when hunting for credential theft via Mimikatz lsadump::dcsync or Impacket secretsdump, investigating lateral movement with domain admin credentials, or auditing AD replication permissions.
Review the instructions the agent will receive before you install.
| Concept | Description |
|---|---|
| T1003.006 | OS Credential Dumping: DCSync |
| DCSync | Mimicking domain controller replication to extract credentials |
| DsGetNCChanges | RPC function used to request AD replication data |
| DS-Replication-Get-Changes | AD permission required (GUID: 1131f6aa-...) |
| DS-Replication-Get-Changes-All | Permission including confidential attributes (GUID: 1131f6ad-...) |
| MS-DRSR | Microsoft Directory Replication Service Remote Protocol |
| KRBTGT Hash | Key target of DCSync enabling Golden Ticket attacks |
| Event ID 4662 | Directory service object access audit event |
| Tool | Purpose |
|---|---|
| Mimikatz (lsadump::dcsync) | Primary DCSync attack tool |
| Impacket secretsdump.py | Python-based DCSync implementation |
| DSInternals | PowerShell module for AD replication |
| BloodHound | Map accounts with replication rights |
| Splunk / Elastic | SIEM correlation of 4662 events |
| Microsoft Defender for Identity | Native DCSync detection |
| CrowdStrike Falcon | EDR-based DCSync detection |
index=wineventlog EventCode=4662
| where Properties IN ("*1131f6aa-9c07-11d1-f79f-00c04fc2dcd2*",
"*1131f6ad-9c07-11d1-f79f-00c04fc2dcd2*",
"*89e95b76-444d-4c62-991a-0facbeda640c*")
| where NOT match(SubjectUserName, ".*\\$$")
| where NOT SubjectUserName IN ("known_svc_account1", "known_svc_account2")
| stats count values(Properties) as ReplicationRights by SubjectUserName SubjectDomainName Computer
| where count > 0
| table SubjectUserName SubjectDomainName Computer count ReplicationRights
SecurityEvent
| where EventID == 4662
| where Properties has "1131f6ad-9c07-11d1-f79f-00c04fc2dcd2"
or Properties has "1131f6aa-9c07-11d1-f79f-00c04fc2dcd2"
| where SubjectUserName !endswith "$"
| where SubjectUserName !in ("AzureADConnect", "MSOL_*")
| project TimeGenerated, SubjectUserName, SubjectDomainName, Computer, Properties
| sort by TimeGenerated desc
title: DCSync Activity Detected - Non-DC Replication Request
status: stable
logsource:
product: windows
service: security
detection:
selection:
EventID: 4662
Properties|contains:
- '1131f6aa-9c07-11d1-f79f-00c04fc2dcd2'
- '1131f6ad-9c07-11d1-f79f-00c04fc2dcd2'
filter_dc:
SubjectUserName|endswith: '$'
condition: selection and not filter_dc
level: critical
tags:
- attack.credential_access
- attack.t1003.006
lsadump::dcsync /user:krbtgt to extract KRBTGT hash for Golden Ticket creation.secretsdump.py domain/user:password@dc-ip extracting all domain hashes.Get-ADReplAccount cmdlet to replicate specific account credentials.Hunt ID: TH-DCSYNC-[DATE]-[SEQ]
Alert Severity: Critical
Source Account: [Account requesting replication]
Source Machine: [Hostname/IP of requestor]
Target DC: [Domain controller receiving request]
Replication Rights: [GUIDs accessed]
Timestamp: [Event time]
Legitimate DC: [Yes/No]
Known Service Account: [Yes/No]
Risk Assessment: [Critical - non-DC replication detected]
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