IoT certificate when root CA security breach

Question

I'm working on IoT devices with Azure IoT Hub + DPS, using the x509 CA authentication method.

I would like to understand the proper way to manage device certificates and root CA renewal in the event of a Root CA security breach.

On the Internet, I mostly find tutorials for renewing device certificates, not root CAs.

This is how I see thing. What I don't like: the device is able to ask the PKI API to sign the newly generated device certificate. Device certificate renewal in case of Root CA security breach

Has anyone experienced this before?

Thank you, Théo

Answer 1

While connecting IOT hub using CA certificate then authorization is compulsory. Key and certificate is extracted from CA certificate and it is used as authorization for connecting to IOT Hub. Once it is extracted then the connection can be done multiple times to already existing IOT hub. New CA certificate details are required only while creating a new IOT hub.

If the Root CA is compromised, you’ll need to revoke the compromised Root CA certificate and generate a new certificate. This process typically involves:

• Generating a new Root CA private key securely and obtain a new Root CA certificate from a trusted certificate authority (CA) or generating a self-signed certificate if self-managed.

• Distributing the new Root CA certificate to all necessary parties and updating trust stores.
  Once the new Root CA certificate is in place, you’ll need to renew the certificates for all affected IoT devices. This process involves:

  • Generating new device certificate signing requests (CSRs) for each device.

  • Submitting the CSRs to the PKI API or CA for signing with the new Root CA certificate.

  • Distributing the newly signed device certificates to the respective devices securely.

  • Revoking the old device certificates to prevent their use.

During the certificate renewal process, ensure that your IoT devices can securely communicate with the PKI API or CA to request and receive new certificates. Implement proper authentication and encryption mechanisms to protect sensitive information during certificate exchange.

NOTE: Usage of X.509 certificate authority (CA) authentication is not yet generally available and Preview mode must be enabled:

• Code is taken from git
  

I followed this document to authenticate with X.509 certificate.