SKILL.md
Implementing Memory Protection with DEP and ASLR
When to Use
Use this skill when hardening endpoints against memory-based exploits by configuring DEP, ASLR, CFG, and Windows Exploit Protection system-wide and per-application mitigations.
Prerequisites
- Windows 10/11 or Windows Server 2016+ with administrative privileges
- Group Policy management access for enterprise-wide deployment
- Understanding of memory corruption attack techniques (buffer overflow, ROP chains)
- Test environment for validating application compatibility with exploit mitigations
Workflow
Step 1: Configure System-Level Mitigations
# Enable system-wide DEP (Data Execution Prevention)
# Boot configuration: OptIn (default), OptOut (recommended), AlwaysOn
bcdedit /set nx AlwaysOn
# Verify ASLR status (enabled by default on modern Windows)
Get-ProcessMitigation -System
# MandatoryASLR, BottomUpASLR, HighEntropyASLR should be ON
# Enable all system-level mitigations
Set-ProcessMitigation -System -Enable DEP,SEHOP,ForceRelocateImages,BottomUp,HighEntropyStep 2: Configure Per-Application Mitigations
# Harden high-risk applications (browsers, Office, PDF readers)
Set-ProcessMitigation -Name "WINWORD.EXE" -Enable DEP,SEHOP,ForceRelocateImages,CFG,StrictHandle
Set-ProcessMitigation -Name "EXCEL.EXE" -Enable DEP,SEHOP,ForceRelocateImages,CFG,StrictHandle
Set-ProcessMitigation -Name "AcroRd32.exe" -Enable DEP,SEHOP,ForceRelocateImages,CFG
Set-ProcessMitigation -Name "chrome.exe" -Enable DEP,CFG,ForceRelocateImages
Set-ProcessMitigation -Name "msedge.exe" -Enable DEP,CFG,ForceRelocateImages
# Export configuration for deployment
Get-ProcessMitigation -RegistryConfigFilePath "C:\exploit_protection.xml"
# Deploy via Intune or GPOStep 3: Deploy via Intune/GPO
Intune: Endpoint Security → Attack Surface Reduction → Exploit Protection
Import exploit_protection.xml template
GPO: Computer Configuration → Admin Templates → Windows Components
→ Windows Defender Exploit Guard → Exploit Protection
→ "Use a common set of exploit protection settings" → Enabled
→ Point to XML file on network shareKey Concepts
| Term | Definition |
|---|---|
| DEP | Marks memory pages as non-executable to prevent shellcode execution in data regions |
| ASLR | Randomizes memory addresses of loaded modules to defeat hardcoded ROP gadgets |
| CFG | Validates indirect call targets at runtime to prevent control flow hijacking |
| SEHOP | Validates SEH chain integrity to prevent SEH-based exploitation |
Tools & Systems
- Windows Exploit Protection: Built-in per-process mitigation management
- EMET (legacy): Enhanced Mitigation Experience Toolkit (predecessor, now deprecated)
- ProcessMitigations PowerShell: Get/Set-ProcessMitigation cmdlets
Common Pitfalls
- DEP compatibility: Legacy 32-bit applications may crash with DEP AlwaysOn. Use OptOut with exceptions.
- Mandatory ASLR breaking apps: Some applications are not ASLR-compatible. Test before enforcing ForceRelocateImages.
- CFG limited to compiled-in support: CFG only works for applications compiled with /guard:cf. Cannot be retroactively applied.