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Introduction:
Entra Connect Sync (formerly Azure AD Connect) is a critical component for hybrid identity management, synchronizing on-premises Active Directory with Azure AD. However, attackers can exploit misconfigurations or vulnerabilities to dump credentials, leading to lateral movement and cloud compromise. This article explores the techniques used and provides actionable mitigation steps.
Learning Objectives:
- Understand how attackers extract Entra Connect Sync credentials.
- Learn defensive techniques to secure hybrid identity synchronization.
- Implement hardening measures for Entra Connect servers.
You Should Know:
1. Dumping Entra Connect Sync Credentials via PowerShell
Attackers often use PowerShell to extract stored credentials from the Entra Connect Sync service.
Command:
Get-ADSyncToolsAADCredential -Verbose
Step-by-Step Explanation:
- Access the Entra Connect Server: Requires local admin privileges.
- Run the Command: Extracts Azure AD credentials stored in the ADSync database.
- Decrypt if Necessary: Some credentials may be encrypted and require additional tools like
Mimikatz.
Mitigation:
- Restrict local admin access to Entra Connect servers.
- Monitor PowerShell execution via SIEM.
2. Extracting Credentials from the ADSync Database
The ADSync database contains sensitive synchronization credentials.
Command:
SELECT FROM mms_management_agent WHERE ma_type = 'AD'
Step-by-Step Explanation:
- Connect to SQL Instance: Entra Connect uses a local SQL instance.
- Query the Database: The `mms_management_agent` table stores sync credentials.
- Decrypt Using ADSycDecrypt: Some fields may require decryption.
Mitigation:
- Encrypt the ADSync database.
- Implement SQL Server auditing.
3. Preventing Credential Theft with LSA Protection
Windows LSA (Local Security Authority) stores secrets in memory, which attackers can extract.
Command (Enable LSA Protection):
New-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\Lsa" -Name "RunAsPPL" -Value 1 -PropertyType DWORD -Force
Step-by-Step Explanation:
1. Modify Registry: Enforces LSA Protection (PPL).
2. Reboot Required: Changes take effect after restart.
Mitigation:
- Enable Credential Guard for additional security.
- Hardening Entra Connect with Privileged Access Workstations (PAW)
Limit administrative access to Entra Connect servers.
Command (Restrict RDP Access):
Set-NetFirewallRule -DisplayGroup "Remote Desktop" -Enabled False -Profile Domain
Step-by-Step Explanation:
1. Block Unnecessary Access: Disables RDP for non-admins.
2. Use PAWs: Dedicated workstations for administrative tasks.
Mitigation:
- Implement Just-In-Time (JIT) access via PIM.
5. Monitoring for Suspicious Sync Activities
Detect abnormal synchronization attempts.
Azure Sentinel Query:
AADConnectHealthSyncJobs | where ResultType == "Failed" and Error contains "Credential"
Step-by-Step Explanation:
- Log into Azure Sentinel: Navigate to Log Analytics.
- Run the Query: Identifies failed sync attempts due to credential issues.
Mitigation:
- Set up alerts for suspicious sync failures.
What Undercode Say:
- Key Takeaway 1: Entra Connect Sync is a high-value target; attackers exploit weak configurations to extract credentials.
- Key Takeaway 2: Proactive hardening (LSA Protection, PAWs, SQL encryption) significantly reduces risk.
Analysis:
Hybrid identity systems remain a prime target for attackers moving from on-prem to cloud. Organizations must treat Entra Connect servers as Tier-0 assets, enforcing strict access controls and monitoring. Failure to do so can lead to full Azure AD compromise.
Prediction:
As hybrid environments grow, credential dumping attacks will increase. Automation tools (like BloodHound for Azure) will make exploitation easier, pushing defenders to adopt Zero Trust and continuous monitoring.
Final Note: Always test security changes in a lab before production deployment. Stay updated with SpecterOps’ latest research (posts.specterops.io).
IT/Security Reporter URL:
Reported By: Florian Hansemann – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
