Securing web applications is a critical component of the Azure Administrator Associate curriculum, specifically within the realm of deploying and managing compute resources. Configuring App Service certificates and Transport Layer Security (TLS) ensures that data transmitted between clients and you…Securing web applications is a critical component of the Azure Administrator Associate curriculum, specifically within the realm of deploying and managing compute resources. Configuring App Service certificates and Transport Layer Security (TLS) ensures that data transmitted between clients and your application remains private and encrypted via HTTPS.
Azure provides flexibility in how certificates are sourced and managed. The simplest method is using **App Service Managed Certificates**, which are free, fully managed by Microsoft, and automatically renewed. While excellent for securing apex domains and subdomains, they do not support wildcard domains. For comprehensive coverage, admins can purchase **App Service Certificates** directly via the Azure Portal, which supports wildcards and integrates with Azure Key Vault for centralized lifecycle management.
Alternatively, administrators can bring their own certificates by uploading PFX files or importing them from Azure Key Vault. Once a certificate is available in the App Service, it must be bound to a custom domain. This **TLS/SSL binding** creates the trust relationship. You typically choose **SNI SSL** (Server Name Indication), which is standard for most modern browsers and allows multiple domains to share an IP, or **IP SSL**, which requires a dedicated IP address.
Finally, configuration management involves enforcing security policies. In the App Service settings, administrators should enable the **HTTPS Only** feature to automatically redirect unencrypted HTTP traffic to HTTPS. Additionally, setting the **Minimum TLS Version** to 1.2 or higher is mandatory for meeting modern security compliance standards, effectively blocking outdated and vulnerable communication protocols.
Configuring App Service Certificates and TLS for AZ-104
What is it? Securing Azure App Services involves using Transport Layer Security (TLS) certificates (often referred to historically as SSL) to encrypt data transmitted between the client (browser) and the web server. While Azure provides a default certificate for the *.azurewebsites.net domain, real-world scenarios and the AZ-104 exam focus on securing Custom Domains with your own certificates.
Why is it important? 1. Encryption: Prevents man-in-the-middle attacks by encrypting data in transit. 2. Trust: Validates the identity of the website servers to the users. 3. Compliance: Most regulatory standards (PCI-DSS, HIPAA) require HTTPS. 4. SEO: Search engines penalize sites that do not use HTTPS.
How it Works: The Configuration Process To secure a custom domain on an App Service, you generally follow these steps:
1. Obtain a Certificate You need a certificate in a .pfx format (which contains the private key) for server-side binding. There are three main ways to get this in Azure: a. App Service Managed Certificate: Free of charge, fully managed by Azure, and easy to create. However, it only supports domain validation and cannot be exported. b. Import from Key Vault: The most secure method for enterprise scenarios. Certificates differ from keys and secrets in Key Vault, but they can be synced to the App Service. c. Upload Certificate: Manually uploading a purchased .pfx file.
2. Create a TLS/SSL Binding Once the certificate is associated with the App Service, you must 'bind' it to a specific hostname. There are two types of SSL bindings you must understand for the exam: Server Name Indication (SNI) SSL: This is the modern standard. Multiple domains can share the same IP address, and the server uses the hostname to know which certificate to present. It allows for unlimited certs and creates no additional cost. IP-based SSL: This is a legacy method. Ideally, only one certificate is assigned to a specific IP address. To use this, you must purchase a Dedicated IP address for the App Service, which incurs higher costs.
3. Enforce HTTPS and TLS Versions After configuring the specific certificate, admins should toggle 'HTTPS Only' to 'On' to redirect all HTTP traffic to HTTPS. Additionally, you can configure the Minimum TLS Version (usually recommended to be 1.2) to reject connections from older, insecure clients.
Exam Tips: Answering Questions on Configure App Service certificates and TLS When facing questions on this topic, look for these keywords to determine the correct answer:
Keyword: 'Minimize Costs' or 'Free' Answer: Use App Service Managed Certificates. Note that these are for custom domains but don't support wildcard domains (unless you buy a specific App Service Domain) or export capabilities.
Keyword: 'Centralized Management' or 'Automatic Rotation' Answer: Import the certificate from Azure Key Vault. This allows you to update the cert in one place (Key Vault) and have it automatically sync to the web app.
Keyword: 'Legacy Browser Support' or 'Non-SNI Client' Answer: Choose IP-Based SSL. Remember, this requires a Basic, Standard, or Premium tier plan and you must ensure you select the option that includes a dedicated IP.
Keyword: 'Private Key' Answer: Remember that for SSL binding, you need a .pfx file (PKCS#12), not a .cer file (which is public key only).
Keyword: 'Security Requirements' for Protocols Answer: If a question asks to disable older protocols (like SSL 3.0 or TLS 1.0/1.1), look for the TLS/SSL settings blade and setting the Minimum TLS Version to 1.2.