Windows Credential Security

Windows Credential Security Analysis

⚠️ Authorization Required

This skill is for authorized security testing and defensive analysis only.

• Only use these techniques on systems you own or have explicit written authorization to test
• Unauthorized credential access is illegal and violates computer crime laws
• Always document authorization before any security assessment
• Use findings to improve security posture, not to exploit vulnerabilities

Purpose

This skill helps security professionals:

• Understand Windows credential storage mechanisms
• Identify attack vectors for authorized penetration testing
• Recommend defensive hardening measures
• Document security findings for authorized assessments
• Analyze indicators of compromise (IoCs)

Credential Storage Overview

LSASS (Local Security Authority Subsystem Service)

What it is: The process that handles Windows authentication and stores credentials in memory

Attack Surface:

• Credentials from interactive logons
• Cached domain credentials
• Kerberos tickets
• NTLM hashes

Defensive Measures:

• Enable Credential Guard (virtualization-based security)
• Enable LSA Protection (RunAsPPL)
• Monitor for LSASS injection attempts
• Use EDR solutions with memory scanning

SAM (Security Account Manager)

What it is: Registry hive storing local account password hashes

Location: C:\Windows\System32\config\SAM

Attack Surface:

• Local user password hashes (NTLM)
• Requires SYSTEM access
• Protected by file permissions

Defensive Measures:

• Use strong local passwords
• Enable LSA protection
• Monitor registry access to SAM hive
• Consider disabling local accounts where possible

NTDS.dit (Active Directory Database)

What it is: The Active Directory database containing domain credentials

Location: %SystemRoot%\NTDS\ntds.dit

Attack Surface:

• All domain user hashes
• Group memberships
• Trust relationships
• Requires SYSTEM + SYSTEM hive for decryption

Defensive Measures:

• Enable AD Credential Guard
• Monitor for NTDS.dit access attempts
• Implement privileged access workstations (PAW)
• Regular security audits of domain controllers

Common Attack Techniques (For Defensive Understanding)

Memory Dumping

Technique: Extracting LSASS memory to obtain credentials

Tools Used (for detection purposes):

• Mimikatz
• Procdump
• SharpDump
• Custom dumpers

Detection Indicators:

• Process injection into LSASS
• Use of MiniDumpWriteDump API
• Access to protected processes
• Registry modifications to LSA settings

Prevention:

• Enable LSA Protection (RunAsPPL)
• Enable Credential Guard
• Monitor for suspicious process access
• Use EDR with memory protection

Registry-Based Extraction

Technique: Copying protected files via registry hives

Detection Indicators:

• reg save commands targeting SAM/SYSTEM/Security hives
• Unusual registry access patterns
• File creation in temp directories

Prevention:

• Monitor registry save operations
• Restrict administrative access
• Implement file integrity monitoring

Volume Shadow Copy Abuse

Technique: Using VSS to copy protected files

Detection Indicators:

• VSS shadow copy creation
• Access to shadow copy volumes
• File copying from shadow copies

Prevention:

• Monitor VSS operations
• Restrict VSS access to administrators
• Implement application whitelisting

Defensive Hardening Recommendations

Registry Settings

# Enable LSA Protection (RunAsPPL)
reg add HKLM\SYSTEM\CurrentControlSet\Control\Lsa /v RunAsPPL /t REG_DWORD /d 1 /f

# Enable Credential Guard
reg add HKLM\SYSTEM\CurrentControlSet\Control\Lsa /v CredentialGuard /t REG_DWORD /d 1 /f

# Disable Restricted Admin (for security)
reg add HKLM\SYSTEM\CurrentControlSet\Control\Lsa /v DisableRestrictedAdmin /t REG_DWORD /d 0 /f

# Enable UAC token filtering
reg add HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v LocalAccountTokenFilterPolicy /t REG_DWORD /d 0 /f

Group Policy Recommendations

1. Enable Credential Guard

   • Computer Configuration → Windows Settings → Security Settings → Local Policies → Security Options
   • "Turn on Virtualization Based Security"

2. Restrict LSASS Access

   • Enable "Run LSA as protected process"

3. Disable NTLM

   • Where possible, use Kerberos authentication
   • Monitor and alert on NTLM usage

4. Implement Least Privilege

   • Remove unnecessary admin rights
   • Use Just-In-Time (JIT) administration

Monitoring Recommendations

Key Events to Monitor:

• Event ID 4688 (Process Creation) - LSASS, procdump, mimikatz
• Event ID 4656 (Handle Requested) - Access to protected files
• Event ID 4663 (Object Access) - Registry hive access
• Event ID 1102 (Audit Log Cleared)
• Event ID 7045 (Service Installation)

EDR Detection Rules:

• Process injection into LSASS
• Use of MiniDumpWriteDump API
• Registry modifications to LSA settings
• Execution of known credential dumping tools

Assessment Documentation Template

When conducting authorized assessments, document:

## Credential Security Assessment

### Scope
- Systems tested: [List]
- Authorization: [Reference]
- Date: [Date]

### Findings

#### LSASS Security
- [ ] Credential Guard enabled
- [ ] LSA Protection enabled
- [ ] Monitoring in place

#### SAM Security
- [ ] Local accounts minimized
- [ ] Strong passwords enforced
- [ ] Registry access monitored

#### Active Directory Security
- [ ] NTDS.dit access monitored
- [ ] Admin access restricted
- [ ] Regular audits performed

### Recommendations
1. [Priority 1]
2. [Priority 2]
3. [Priority 3]

Tools for Defensive Analysis

Detection Tools

• Sysmon - Enhanced process and network monitoring
• OSQuery - SQL-based system querying
• Velociraptor - Endpoint detection and response
• Sigma - Detection rule format

Analysis Tools

• Volatility - Memory forensics
• Mimikatz (authorized use only) - Understanding attack techniques
• Impacket - Network protocol analysis

References

• Microsoft Credential Guard Documentation
• MITRE ATT&CK - Credential Access
• CIS Benchmarks for Windows

Important Notes

1. Legal Compliance: Always ensure you have proper authorization before testing
2. Documentation: Document all findings and recommendations
3. Remediation: Work with system owners to implement fixes
4. Continuous Monitoring: Security is ongoing, not one-time
5. Training: Educate users about credential security best practices

When to Use This Skill

Use this skill when:

• Planning authorized penetration tests
• Assessing Windows credential security posture
• Investigating potential credential theft incidents
• Developing defensive hardening strategies
• Creating security documentation and reports
• Training security teams on credential protection

Do NOT use this skill for:

• Unauthorized access to systems
• Malicious credential theft
• Activities without proper authorization
• Any illegal or unethical purposes