Revoking SSL/TLS certificates is an important security measure in cases where the private key has been compromised, the certificate was issued incorrectly, or if the certificate is no longer needed. Let's walk through the steps to revoke a certificate with Certbot:
Step 1: Identify the certificate to revoke
First, identify the SSL/TLS certificate that you want to revoke. You'll need to know the certificate's serial number or its SHA-1 or SHA-256 fingerprint. You can find this information by running the following command:
sudo certbot certificates
This command will display a list of certificates managed by Certbot, along with their serial numbers and fingerprints.
Step 2: Revoke the certificate
Once you have identified the certificate to revoke, use the certbot revoke command to revoke it. You'll need to specify the certificate's serial number or fingerprint, as well as the reason for revocation (e.g., key-compromise, affiliation-changed, cessation-of-operation, or superseded).
sudo certbot revoke --cert-path /path/to/certificate.pem --reason <reason>
Replace /path/to/certificate.pem with the path to the certificate file, and <reason> with one of the revocation reasons listed above.
Alternatively, you can use the --cert-name option to specify the certificate by its Certbot-managed name:
sudo certbot revoke --cert-name example.com --reason <reason>
Step 3: Confirm revocation
After revoking the certificate, Certbot will attempt to notify the certificate authority (e.g., Let's Encrypt) of the revocation. You may receive a confirmation message if the revocation is successful.
Step 4: Remove revoked certificate
Once the certificate has been revoked, you may want to remove it from your server to prevent accidental use. Delete the certificate files from their respective locations on your server.
Additional Considerations
- Revoking a certificate invalidates it immediately, so only revoke a certificate if it is compromised or no longer needed.
- Keep in mind that revocation does not remove the certificate from public Certificate Transparency logs, so revoked certificates may still be discoverable.
- After revoking a certificate, you should replace it with a new one if necessary, either by obtaining a new certificate or restoring from a backup.
By following these steps, you can revoke SSL/TLS certificates with Certbot when necessary, helping to maintain the security of your server and protect against misuse of compromised certificates.