Getting Started with Microsoft SC-900 Security Fundamentals: A Guide for IAM Professionals

01Problem Statement: Securing Modern Applications with Microsoft Azure AD

Securing modern cloud applications is inherently complex, especially when leveraging Microsoft Azure Active Directory (Azure AD) as your Identity Provider (IdP). The challenge lies in balancing usability with robust security while adhering to industry standards like OAuth 2.1, OpenID Connect (OIDC) 1.0, and SCIM 2.0.

Common pitfalls include:

• Misconfigured token expiration policies leading to security vulnerabilities
• Inadequate logging and monitoring of authentication events
• Overly permissive role assignments increasing the attack surface

This guide provides a hands-on approach to securing your Azure AD environment, with a focus on real-world implementation details.

02Core Concepts: Azure AD Architecture and Components

Azure AD Components

1. Tenant: Your organization's instance of Azure AD (e.g., contoso.onmicrosoft.com)
2. App Registrations: Define your application's identity and permissions
3. Enterprise Applications: Pre-built integrations with SaaS apps
4. Role-Based Access Control (RBAC): Granular permissions management
5. Conditional Access Policies: Context-aware access controls

Key Protocols

• OAuth 2.1: Authorization framework (RFC 9207)
• OpenID Connect 1.0: Authentication layer on top of OAuth (RFC 8252)
• SCIM 2.0: User provisioning standard (RFC 7644)

03Authentication Flow: Implementing OIDC with Azure AD

Authorization Code Flow

The standard flow for web applications:

Key Configuration Parameters

Security Considerations

• Token Binding: Ensure tokens are bound to the client's IP and user agent
• PKCE (Proof Key for Code Exchange): Required for public clients (RFC 7636)

04Authorization: Implementing RBAC and Conditional Access

Role-Based Access Control (RBAC)

Azure AD supports three types of roles:

1. Azure Built-in Roles: Predefined roles (e.g., Reader, Contributor)
2. Custom Roles: Define your own permissions
3. Application Roles: Custom roles within your application

Conditional Access Policies

Conditional access enforces access policies based on:

• Device state (e.g., compliant/non-compliant)
• Location (e.g., block access from specific regions)
• Time of day
• Client application (e.g., only allow Microsoft Authenticator)

Example Conditional Access Policy

{
 "displayName": "Require MFA for Admins",
 "conditions": {
 "clientApplications": ["Microsoft Authenticator"],
 "signInRiskLevels": ["high"]
 },
 "grantControls": {
 "builtInControls": ["multiFactorAuthentication"]
 }
}

Gotchas

• Overly Restrictive Policies: Can block legitimate users
• Policy Evaluation Order: Earlier policies can override later ones

05Implementation Trade-offs: On-Prem vs Cloud

On-Premises AD vs Azure AD

Pros and Cons

06Common Mistakes and How to Avoid Them

Mistake 1: Insecure Token Storage

• Issue: Storing tokens in insecure locations (e.g., localStorage)
• Solution: Use secure HTTP-only cookies

Mistake 2: Overly Permissive Scopes

• Issue: Requesting unnecessary scopes (e.g., openid profile email)
• Solution: Use the principle of least privilege

Mistake 3: Ignoring Token Expiration

• Issue: Failing to refresh tokens before expiration
• Solution: Implement token refresh logic

07Unpopular Opinion: Azure AD is Too Feature-Rich

While Azure AD offers an extensive set of features, its complexity can be overwhelming for smaller organizations. Consider alternative lightweight IAM solutions like Keycloak if your needs are simpler.

08Conclusion

Securing your application with Azure AD requires careful planning and attention to detail. By following the guidelines in this article, you can implement a secure, scalable IAM solution that meets the needs of your organization.

09Quick Reference

Key Azure AD CLI Commands

az ad app create --display-name " MyApp"
az ad app show --id <app-id>
az ad app update --id <app-id> --set replyUrls="https://myapp.com"

Recommended OIDC Configuration

{
 "auth": {
 "authority": "https://login.microsoftonline.com/contoso.onmicrosoft.com",
 "clientId": "12345678-9abc-defg-hijk-lmnopqrstuvw",
 "redirectUri": "https://myapp.com/auth/callback",
 "responseType": "code",
 "scope": "openid profile email"
 }
}

Common Scopes