Email Verification with MSAL and Azure Functions

Getting Started with MSAL Authentication

Implementing authentication and authorization in modern applications is crucial for ensuring data security and user management. In scenarios where Microsoft Azure and its services are involved, leveraging Microsoft Authentication Library (MSAL) provides a robust solution. This guide focuses on a common challenge: verifying user emails during the login process and ensuring they belong to the correct tenant.

Additionally, the process involves retrieving users' full names once their email addresses are authenticated. This dual verification process is particularly vital in corporate environments where email verification can prevent unauthorized access and ensure that user registrations are valid within the company's domain. The approach discussed uses Azure Functions to handle the backend logic, enhancing scalability and manageability of the authentication process.

Script Explanation and Utility Overview

The script provided is designed to authenticate and verify the identity of users within a specific Microsoft Azure tenant using MSAL (Microsoft Authentication Library) and Azure Functions. The primary command, ConfidentialClientApplication, is crucial as it sets up the MSAL client which interacts with Microsoft's identity platform. This setup includes the necessary client and tenant details for authentication. The axios.get function then plays a pivotal role by sending requests to Microsoft Graph API to retrieve user details such as email and full name, ensuring the user's provided email matches the one associated with their Azure identity.

The Express.js framework, utilized here through commands like app.use(json()) and app.post, is employed to handle incoming HTTP requests and responses. The app.post handler is specifically designed to process POST requests that contain the user's email and access token. By decoding the token and validating it against the provided email, the script ensures that the email not only belongs to the tenant but is also an active, valid user in the directory. This method provides a secure way to authenticate user actions and manage access within corporate environments.

Enhancing User Verification with MSAL and Azure Functions

JavaScript and Node.js Implementation

const { ConfidentialClientApplication } = require('@azure/msal-node');
const axios = require('axios');
const { json } = require('express');
const express = require('express');
const app = express();
app.use(json());

const msalConfig = {
    auth: {
        clientId: "YOUR_CLIENT_ID",
        authority: "https://login.microsoftonline.com/YOUR_TENANT_ID",
        clientSecret: "YOUR_CLIENT_SECRET",
    }
};

const cca = new ConfidentialClientApplication(msalConfig);
const tokenRequest = {
    scopes: ["user.Read.All"],
    skipCache: true,
};

async function getUserDetails(userEmail, accessToken) {
    const graphEndpoint = \`https://graph.microsoft.com/v1.0/users/\${userEmail}\`;
    try {
        const userResponse = await axios.get(graphEndpoint, { headers: { Authorization: \`Bearer \${accessToken}\` } });
        return { email: userResponse.data.mail, fullName: userResponse.data.displayName };
    } catch (error) {
        console.error('Error fetching user details:', error);
        return null;
    }
}

app.post('/verifyUser', async (req, res) => {
    const { emailToVerify } = req.body;
    const authHeader = req.headers.authorization;
    const accessToken = authHeader.split(' ')[1];
    const userDetails = await getUserDetails(emailToVerify, accessToken);
    if (userDetails && userDetails.email === emailToVerify) {
        res.status(200).json({
            message: 'User verified successfully.',
            fullName: userDetails.fullName
        });
    } else {
        res.status(404).json({ message: 'User not found or email mismatch.' });
    }
});

app.listen(3000, () => console.log('Server running on port 3000'));

Advanced Integration Techniques for MSAL and Azure Functions

Integrating MSAL (Microsoft Authentication Library) with Azure Functions allows developers to create more secure and scalable applications by handling authentication processes serverlessly. This setup not only improves security by centralizing authentication logic but also enhances performance, as Azure Functions can scale based on demand without provisioning or managing servers. The primary benefit of this architecture is the ability to efficiently manage user identities and access controls across a wide range of services within the Microsoft identity platform ecosystem.

Moreover, this approach facilitates the implementation of complex authentication scenarios, such as conditional access, multi-factor authentication, and seamless single sign-on (SSO) across applications. By leveraging Azure Functions, developers can execute authentication-related functions triggered by HTTP requests, process tokens, and perform user validation against Microsoft Graph API to fetch user details securely and efficiently. Such capabilities are crucial for enterprises that require robust identity management solutions to protect their resources.

Common Questions on MSAL Authentication with Azure Functions

1. Question: What is MSAL and how does it work with Azure Functions?
2. Answer: MSAL (Microsoft Authentication Library) is a library designed to help developers authenticate users and access tokens from the Microsoft identity platform. It integrates with Azure Functions to secure APIs by validating tokens and managing users.
3. Question: Can Azure Functions handle token refresh scenarios?
4. Answer: Yes, Azure Functions can be configured to handle token refresh scenarios by utilizing MSAL’s built-in capabilities to automatically manage the lifecycle of tokens, including refreshing them when they expire.
5. Question: How do you secure Azure Functions with MSAL?
6. Answer: Securing Azure Functions involves configuring the function app with the appropriate authentication settings using MSAL, implementing function-level authentication, and ensuring tokens are validated for each request.
7. Question: What scopes are needed to verify a user’s email in Azure?
8. Answer: To verify a user's email using MSAL and Azure Functions, you typically need the `User.Read` or `User.ReadBasic.All` scope, which allows the application to read the basic profile of authenticated users.
9. Question: How do I handle errors in authentication with Azure Functions?
10. Answer: Error handling in Azure Functions can be achieved by implementing try-catch blocks within the function code to catch and respond to authentication or API call failures, thus ensuring robust error management and response strategies.

Final Insights on MSAL Authentication with Azure Functions

Implementing robust user verification in applications utilizing MSAL and Azure Functions offers enhanced security and streamlined user management. This approach is essential for applications requiring reliable identity verification to maintain secure and efficient operations. By integrating MSAL with Azure Functions, developers can efficiently manage authentication flows, handle large volumes of authentication requests, and provide users with a secure and seamless experience. This method not only secures applications but also aligns with modern cloud-based architecture, making it a valuable choice for enterprise environments.