Providing Password Reset Codes with Single-Use Validity in Azure AD B2C Custom Policies

Securing Password Resets in Azure AD B2C with One-Time Verification Codes

Ensuring that email verification codes are used only once is a common difficulty faced by developers when building a safe and intuitive password reset procedure within Azure AD B2C. In order to safeguard user accounts from unwanted access and preserve the integrity of the authentication process, this feature is essential. A built-in mechanism for single-use verification codes is present in traditional B2C user flows; if a code is attempted to be reused, the user is prompted to request a new one. A key component of safe digital identity management procedures is this behavior.

But Azure AD B2C custom policies present a more complex problem. Developers discover that these regulations deviate from the anticipated single-use requirement by permitting the verification code to be used more than once during its validity period. Because it could allow hostile actors to obtain access by repeatedly utilizing the same verification code, this issue presents serious security issues. Next, the challenge is to duplicate in custom policies the built-in behavior of Azure AD B2C user flows, making sure that a verification code is never reused for further password reset attempts after it has been used.

Command	Description
require('express')	Imports the Express framework in order to build an online program.
express.Router()	To handle routes, creates a new router object.
require('bcrypt')	Opens the bcrypt library and uses it to compare and hash passwords.
require('jsonwebtoken')	Uses the jsonwebtoken library to import JWT tokens and create and verify them.
router.post('/path', async (req, res) => {})	Defines a POST route with the function being the route handler and the endpoint being "/path."
await User.findOne({ email })	Email-based asynchronous search for a single user in the database
Math.floor(Math.random() * range)	Produces a random number between two given values.
await bcrypt.hash(data, saltRounds)	Hashes a piece of data asynchronously using a predetermined number of salt rounds
new Model({ ... })	Generates a new model instance with the given characteristics.
await modelInstance.save()	Saves the model instance to the database asynchronously
res.send('message')	Delivers a message in response to the customer
await bcrypt.compare(data, encrypted)	Compares a piece of data with an encrypted hash asynchronously

Examining the Mechanism for Single-Use Verification Codes

For the purpose of improving security and integrity of the reset process, the Node.js and Express scripts created to address the difficulty of guaranteeing that a verification code for password reset in Azure AD B2C custom policies is used only once are essential. The Express framework lies at the core of the backend logic; it makes it easier to create a web application server and define API endpoints for handling verification code validation and password reset requests. First, when a user requests a password reset, a special, temporary verification code is generated. This is accomplished by using the bcrypt library to safely hash the random six-digit integer that is generated by the Math object. The hashed code is then kept in the database linked to the user's account, along with a flag indicating that it is currently unused.

The system first obtains the code linked to the user's account from the database, making sure it hasn't been marked as used, before attempting to reset the password using the verification code. Here, the bcrypt.compare function is essential because it safely compares the input code with the hashed version that is saved. The script records the code as used in the database and resets the password if the comparison is successful and the code has never been used before. By preventing the reuse of verification codes and bringing the custom policy's behavior into line with typical B2C user flows, this solution effectively reduces the security concerns that may arise from using a single verification code more than once.

const express = require('express');
const router = express.Router();
const bcrypt = require('bcrypt');
const jwt = require('jsonwebtoken');
const User = require('../models/user'); // Assume a User model is defined
const VerificationCode = require('../models/verificationCode'); // Model for storing verification codes

// Endpoint to request a password reset
router.post('/requestReset', async (req, res) => {
  const { email } = req.body;
  const user = await User.findOne({ email });
  if (!user) {
    return res.status(404).send('User not found');
  }
  const code = Math.floor(100000 + Math.random() * 900000); // Generate 6 digit code
  const hashedCode = await bcrypt.hash(code.toString(), 12);
  const verificationEntry = new VerificationCode({ userId: user._id, code: hashedCode, used: false });
  await verificationEntry.save();
  // Send code via email here (implementation depends on email service)
  res.send('Verification code sent');
});

// Endpoint to verify code and reset password
router.post('/resetPassword', async (req, res) => {
  const { email, code, newPassword } = req.body;
  const user = await User.findOne({ email });
  if (!user) {
    return res.status(404).send('User not found');
  }
  const verificationEntry = await VerificationCode.findOne({ userId: user._id, used: false });
  if (!verificationEntry) {
    return res.status(400).send('No verification code found or code already used');
  }
  const validCode = await bcrypt.compare(code, verificationEntry.code);
  if (!validCode) {
    return res.status(400).send('Invalid verification code');
  }
  verificationEntry.used = true;
  await verificationEntry.save();
  user.password = await bcrypt.hash(newPassword, 12); // Hash new password
  await user.save();
  res.send('Password has been reset');
});

Improving Azure AD B2C Security Using Single-Use Verification Codes

Beyond the application of one-time verification codes, there is a more comprehensive context related to Azure AD B2C custom rules that should be taken into account, particularly with regard to security and user experience. Preventing attacks like replay attacks, which take advantage of the reuse of verification codes, is a major reason for the introduction of single-use codes. These attacks happen when a code is intercepted and used by an attacker before the intended user. You may successfully eliminate this danger vector by making sure that each code is only good for one usage. Furthermore, by reducing the possibility of user misunderstanding and annoyance resulting from unintentional code reuse or malicious party interception, this approach helps to improve the efficiency of the user experience.

Furthermore, integrating single-use verification codes into Azure AD B2C custom policies calls for a strong back-end system that can handle every code's lifespan, from creation and transmission to validation and expiration. This system needs to be carefully crafted to strike a compromise between use and security, making sure that codes expire after a certain amount of time or after successful usage. The implementation of this functionality might potentially involve informing users in real-time on the status of their codes, thereby augmenting the security and responsiveness of the password reset procedure. This method protects digital identities from a variety of cybersecurity threats and is in line with best practices for identity access management (IAM).

In summary, integrating single-use verification codes into Azure AD B2C custom policies is essential for improving security and guaranteeing a smooth user experience throughout the password reset process. By reducing the dangers of replay attacks and other issues related to the reuse of verification codes, this tactic protects user accounts from unwanted access. In order to monitor and invalidate codes after their initial use, the technical solution combines secure code creation, efficient database management, and backend programming. By doing this, businesses may help users feel more confident while also adhering to identity and access management best practices. It is crucial to strike a balance between security precautions and user ease, which emphasizes how crucial it is to continuously assess and enhance authentication procedures. The ultimate objective is to establish a safe, intuitive environment that safeguards digital identities and gives consumers the assurance they need to interact with online services with confidence.