ACME
Automatic Certificate Management Environment
A protocol with which a client proves control of a domain, usually through an HTTP-01 or DNS-01 challenge, and obtains and renews certificates without manual steps, as with Let’s Encrypt. Automation matters more as the maximum lifetime of publicly trusted TLS certificates falls toward 47 days in 2029.
- Defined in
- RFC 8555
Covered in
Operate TLS and certificates: configuration, renewal and verification
Configure a modern TLS profile with hybrid post-quantum key exchange, automate renewal for certificate lifetimes that fall to 47 days, and verify every termination point with a fresh handshake.
Prevent subdomain takeover from dangling DNS records
A DNS record that outlives its cloud resource lets whoever claims the name serve content on your domain. Bind records to resources in IaC, remove the record first, verify domains and scan for dangling records.
Case study: certificate expiry outages at Ericsson (2018) and Microsoft Teams (2020), and Equifax's blind spot
How an expired certificate inside Ericsson's core-network software cut mobile data for millions in about 11 countries, how an expired authentication certificate took Microsoft Teams offline, how an expired inspection certificate left Equifax blind for 19 months, through its 2017 breach, and the inventory, automation and testing that prevent each.