ICT-Governance-Framework-Application

Microsoft Defender Application Control with AppCatalog Integration

This document provides implementation guidance for integrating Microsoft Defender Application Control (MDAC) with an application catalog in your ICT governance framework, managed through Infrastructure as Code.

Purpose

Defender Application Control provides a robust mechanism for controlling which applications and code can run in your environment. Integrating it with your application catalog ensures that:

  1. Only approved applications can run on organizational devices
  2. Applications are automatically cataloged, inventoried, and monitored
  3. Application security is managed as code and governed through the same pipelines as other infrastructure

Implementation Approach

1. Defender Application Control Configuration as Code

Use the following approach to manage MDAC configurations as code:

# Sample Intune Configuration Profile for MDAC (as ARM template or Bicep)
resource "intuneDeviceConfiguration" {
  name: "MDAC-Base-Configuration"
  properties: {
    displayName: "MDAC Base Policy Configuration"
    description: "Base Defender Application Control configuration enforced by ICT Governance Framework"
    settings: {
      applicationControl: {
        mode: "Audit" // Initially in audit mode, later enforced
        appLockerApplicationControl: {
          appLockerEnabled: true
          requireDigitalSignatures: true
          userExemptions: []
          userDefinedFileTypes: []
        }
      }
    }
  }
}

2. AppCatalog Integration

Link your application catalog with MDAC through Azure Functions and custom APIs:

  1. Application Registry Database:
    • Implement using Azure SQL or Cosmos DB
    • Track approved applications, versions, and compliance status
    • Store application metadata, including:
      • Publisher information
      • Version details
      • Hash values
      • Signing certificates
      • Deployment requirements
  2. Catalog Synchronization Process:
    • Deploy an Azure Function to synchronize catalog with MDAC policies
    • Implement scheduled execution through Azure Logic Apps
    • Version control the synchronization code alongside infrastructure
# Sample catalog synchronization code
function Sync-ApplicationCatalog {
    param (
        [string]$catalogApiEndpoint,
        [string]$mdacPolicyId
    )
    
    # 1. Get approved applications from catalog
    $approvedApps = Invoke-RestMethod -Uri $catalogApiEndpoint
    
    # 2. Transform to MDAC format
    $mdacRules = $approvedApps | ForEach-Object {
        @{
            FilePath = $_.ExecutablePath
            FileHash = $_.FileHash
            Publisher = $_.Publisher
            Version = $_.Version
        }
    }
    
    # 3. Update MDAC policy
    Update-MDACPolicy -PolicyId $mdacPolicyId -Rules $mdacRules
}

3. Repository Structure

Maintain MDAC configurations in your Infrastructure as Code repository:

/infrastructure/
  ├── /security/
  │   ├── /mdac/
  │   │   ├── base-policy.bicep        # Base MDAC policy
  │   │   ├── catalog-integration.bicep # AppCatalog integration resources
  │   │   ├── exception-process.bicep   # Exception handling workflow
  │   │   └── reporting.bicep          # Compliance reporting
  │   └── /appcatalog/
  │       ├── database.bicep           # Application registry database
  │       ├── api.bicep                # Catalog API resources
  │       ├── sync-function.bicep      # Synchronization function
  │       └── admin-portal.bicep       # Admin portal for catalog management

CI/CD Integration

Integrate application catalog and MDAC management into your CI/CD pipelines:

  1. Validation Stage:
    • Validate MDAC policy syntax
    • Verify catalog integrity and schema compliance
    • Test synchronization process
  2. Deployment Stage:
    • Deploy updated MDAC policies
    • Update catalog API and database schema
    • Rollout changes with appropriate sequencing
  3. Verification Stage:
    • Verify policy application
    • Validate catalog accessibility
    • Confirm synchronization functionality
# Sample pipeline stage for AppCatalog and MDAC
stages:
  - stage: DeployAppCatalogAndMDAC
    jobs:
      - job: DeployDatabase
        steps:
          - template: templates/deploy-sql-database.yml
            parameters:
              databaseName: 'AppCatalogDB'
              
      - job: DeployAPI
        dependsOn: DeployDatabase
        steps:
          - template: templates/deploy-api.yml
            parameters:
              apiName: 'AppCatalogAPI'
              
      - job: DeployMDACPolicy
        dependsOn: DeployAPI
        steps:
          - task: AzurePowerShell@5
            inputs:
              azureSubscription: $(azureSubscription)
              ScriptType: 'FilePath'
              ScriptPath: '$(System.DefaultWorkingDirectory)/scripts/Deploy-MDACPolicy.ps1'
              ScriptArguments: '-CatalogApiEndpoint $(catalogApiEndpoint) -PolicyId $(mdacPolicyId)'

Security Considerations

  1. Least Privilege Access:
    • Implement RBAC for catalog and MDAC management
    • Separate duties between catalog approvers and infrastructure deployers
  2. Change Control:
    • All MDAC policy changes must follow governance approval process
    • Policy exceptions require documented justification and approval
  3. Compliance Monitoring:
    • Monitor MDAC audit logs for unauthorized application executions
    • Set up alerts for policy overrides or enforcement failures
  4. Emergency Response:
    • Create emergency override procedures for critical scenarios
    • Document rollback procedures for problematic MDAC policies

Integration with Employee App Store

The Defender AppCatalog integration works in conjunction with the Employee App Store:

  1. Apps approved in the governance process are added to the AppCatalog
  2. MDAC policies are automatically updated to allow these applications
  3. The Employee App Store displays and distributes only approved applications
  4. Compliance reporting shows application usage across the organization

Employee Validation and SIEM/Cloud App Security Integration

To ensure comprehensive visibility and governance of all applications used on company devices:

  1. SIEM and Cloud App Security Integration:
    • Implement real-time integration with Microsoft Sentinel and/or Microsoft Defender for Cloud Apps
    • Automatically detect and catalog applications discovered by security monitoring tools
    • Generate alerts for unauthorized application usage
  2. Complete Application Inventory:
    • The AppCatalog must include ALL applications used during employee activities on company devices
    • Cover both installed applications and web/SaaS applications
    • Track application usage across different environments (on-premises, cloud, mobile)
  3. Employee Validation Process:
    • Implement a validation workflow for applications detected but not yet in the catalog
    • Employees receive notifications when using uncataloged applications
    • Self-service portal for submitting application validation requests
    • Automated risk assessment based on app reputation and behavior
# Sample AppCatalog validation workflow
resource "logicApp" {
  name: "AppCatalog-ValidationWorkflow"
  properties: {
    definition: {
      triggers: {
        # Trigger when SIEM/Cloud App Security detects new application
        when_new_app_detected: {}
      },
      actions: {
        # Check if app exists in catalog
        check_catalog: {},
        # If not in catalog, create validation request
        create_validation_request: {},
        # Notify employee and security team
        send_notifications: {},
        # Route for approval based on risk score
        route_for_approval: {}
      }
    }
  }
}
  1. Integration with Identity Governance:
    • Link application usage to user identities and groups
    • Enable conditional access policies based on application risk levels
    • Enforce application usage policies based on user roles and responsibilities
  2. Closed-Loop Validation:
    • Applications identified by security tools must be validated or blocked
    • Regular reconciliation between SIEM/Cloud App Security data and AppCatalog
    • Automated compliance reporting for application usage

Metrics and Reporting

Implement the following metrics to track AppCatalog effectiveness:

Metric Description Target Reporting Frequency
Catalog Coverage Percentage of applications in use that are in the catalog >98% Weekly
Unauthorized Execution Rate Attempts to run unauthorized applications <1% Daily
Catalog Update Time Time from approval to availability in catalog <24 hours Monthly
Exception Request Resolution Time Time to resolve exception requests <48 hours Monthly
SIEM/CAS Discovery Rate New applications discovered by security tools Trending down Weekly
Employee Validation Response Percentage of validation requests addressed by employees >95% Weekly
Shadow IT Coverage Percentage of cloud apps identified and cataloged >99% Monthly
Application Risk Profile Distribution of applications by risk level <5% high risk Monthly

Implementation Roadmap

Phase 1: Foundation (1-2 months)

Week 1-2: Infrastructure Setup

Week 3-4: Core Functionality

Week 5-6: Security Integration

Week 7-8: Testing and Optimization

Phase 2: Integration (2-4 months)

Month 1: Synchronization Implementation

Month 2: User Experience Development

Month 3: Advanced Integration

Month 4: Security Enhancement

Phase 3: Enforcement (4-6 months)

Month 1: Controlled Enforcement

Month 2: Workflow Automation

Month 3: Advanced Validation

Month 4: User Experience Enhancement

Month 5-6: Optimization and Scale

Phase 4: Continuous Improvement (Ongoing)

Quarterly Activities

Monthly Activities

This implementation guidance aligns with the ICT Governance Framework’s principles while providing specific guidance for Microsoft Defender Application Control integration with your application catalog, all managed through Infrastructure as Code.

For more detailed implementation guidance, refer to the following documents:

  1. Employee App Store API - Detailed implementation of the API for employee app store
  2. Integration Implementation Plan - Comprehensive plan for integrating all components
  3. SIEM and Cloud App Security Integration Design - Technical design for security tool integration

These documents provide detailed technical specifications, implementation timelines, and resource requirements for successfully deploying the integrated application governance ecosystem.

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