Configuring TLS 1.2 cipher suites or just enabling TLS 1.3: which earns your tuning time?

Configuring TLS 1.2 cipher suites or just enabling TLS 1.3: which earns your tuning time?

Where should you spend effort hardening cipher selection? The two protocol versions demand completely different amounts of it, and conflating them wastes work.

TLS 1.2 exposes a sprawling, error-prone cipher-suite space: you must explicitly disable RC4, 3DES, CBC-mode suites vulnerable to padding oracles, and static-RSA key exchange that lacks forward secrecy, while ordering ECDHE-AEAD suites first. Getting the ordering and the exclusions right is genuine work.

TLS 1.3 (RFC 8446) removed the foot-guns by design. It supports only five AEAD suites, mandates forward secrecy via ephemeral key exchange, and dropped renegotiation, compression, and static RSA. There is almost nothing to misconfigure in the cipher space — the security comes from the protocol, not from your ordering.

— Spend your hardening budget on the TLS 1.2 suite list, not on 1.3.
— On 1.3, accept the default five suites; reordering buys nothing meaningful.
— Disable TLS 1.0/1.1 entirely; they are deprecated by RFC 8996.

Further reading: RFC 8446 §B.4; RFC 8996; Mozilla's TLS configuration generator.

Bottom line: TLS 1.2 is where cipher tuning pays off; TLS 1.3's restricted suite set makes the same effort redundant — prioritize accordingly.