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mukul975
74 lines
3.0 KiB
Markdown
74 lines
3.0 KiB
Markdown
---
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name: hunting-for-dcsync-attacks
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description: Detect DCSync attacks by analyzing Windows Event ID 4662 for unauthorized DS-Replication-Get-Changes requests from non-domain-controller accounts.
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domain: cybersecurity
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subdomain: threat-hunting
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tags: [threat-hunting, dcsync, active-directory, credential-access, t1003.006, mimikatz, windows, dfir]
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version: "1.0"
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author: mahipal
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license: Apache-2.0
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---
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# Hunting for DCSync Attacks
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## When to Use
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- When hunting for DCSync credential theft (MITRE ATT&CK T1003.006)
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- After detecting Mimikatz or similar tools in the environment
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- During incident response involving Active Directory compromise
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- When monitoring for unauthorized domain replication requests
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- During purple team exercises testing AD attack detection
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## Prerequisites
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- Windows Security Event Log forwarding enabled (Event ID 4662)
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- Audit Directory Service Access enabled via Group Policy
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- Domain Computers SACL configured on Domain Object for machine account detection
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- SIEM with Windows event data ingested (Splunk, Elastic, Sentinel)
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- Knowledge of legitimate domain controller accounts and replication partners
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## Workflow
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1. **Enable Auditing**: Ensure Audit Directory Service Access is enabled on domain controllers.
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2. **Collect Events**: Gather Windows Event ID 4662 with AccessMask 0x100 (Control Access).
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3. **Filter Replication GUIDs**: Search for DS-Replication-Get-Changes and DS-Replication-Get-Changes-All.
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4. **Identify Non-DC Sources**: Flag events where SubjectUserName is not a domain controller machine account.
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5. **Correlate with Network**: Cross-reference source IPs against known DC addresses.
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6. **Validate Findings**: Exclude legitimate replication tools (Azure AD Connect, SCCM).
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7. **Respond**: Disable compromised accounts, reset krbtgt, investigate lateral movement.
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## Key Concepts
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| Concept | Description |
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|---------|-------------|
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| DCSync | Technique abusing AD replication protocol to extract password hashes |
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| Event ID 4662 | Directory Service Access audit event |
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| DS-Replication-Get-Changes | GUID 1131f6aa-9c07-11d1-f79f-00c04fc2dcd2 |
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| DS-Replication-Get-Changes-All | GUID 1131f6ad-9c07-11d1-f79f-00c04fc2dcd2 |
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| AccessMask 0x100 | Control Access right indicating extended rights verification |
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| T1003.006 | OS Credential Dumping: DCSync |
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## Tools & Systems
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| Tool | Purpose |
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|------|---------|
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| Windows Event Viewer | Direct event log analysis |
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| Splunk | SIEM correlation of Event 4662 |
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| Elastic Security | Detection rules for DCSync patterns |
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| Mimikatz lsadump::dcsync | Attack tool used to perform DCSync |
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| Impacket secretsdump.py | Python-based DCSync implementation |
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| BloodHound | Identify accounts with replication rights |
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## Output Format
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```
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Hunt ID: TH-DCSYNC-[DATE]-[SEQ]
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Technique: T1003.006
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Domain Controller: [DC hostname]
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Subject Account: [Account performing replication]
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Source IP: [Non-DC IP address]
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GUID Accessed: [Replication GUID]
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Risk Level: [Critical/High/Medium/Low]
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Recommended Action: [Disable account, reset krbtgt, investigate]
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```
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