Use Custom SMS Provider for Phone Message MFA

Knowledge Articles
1

Overview

This article explains how to use a custom SMS provider for phone message Muti-factor Authentication (MFA).

Applies To

  • Custom SMS
  • Muti-factor Authentication (MFA)

Solution

This can be achieved using a Send Phone Message action to customize how the OTP should be sent.

Here is an example that uses SNS:

const AWS = require("aws-sdk");

/**
 * Handler that will be called during the execution of a SendPhoneMessage flow.
 *
 * @param {Event} event - Details about the user and the context in which they are logging in.
 */
exports.onExecuteSendPhoneMessage = async (event) => {
  const text = event.message_options.text;
  const recipient = event.message_options.recipient;

  const awsSNS = new AWS.SNS({
    apiVersion: "2010-03-31",
    region: event.secrets.AWS_REGION,
    credentials: new AWS.Credentials(event.secrets.AWS_ACCESS_KEY_ID, event.secrets.AWS_SECRET_ACCESS_KEY)
  });

  const params = { Message: text, PhoneNumber: recipient };

  return awsSNS
    .publish(params)
    .promise();
};

It is necessary to customise the Phone Message delivery provider settings to use Custom instead of the built-in provider.