Protocols & PKILegacy - avoid
SSL 2.0, SSL 3.0, TLS 1.0 and TLS 1.1
Obsolete secure transport protocols
How it works
SSL was Netscape's original secure transport protocol, and TLS 1.0 and 1.1 were its early IETF successors. They depend on constructions now known to be weak, such as SHA-1 and MD5 in the handshake, predictable CBC IVs and RC4. Modern browsers and servers have disabled all of them.
Status: SSL 2.0 and 3.0 are prohibited; TLS 1.0 and 1.1 were formally deprecated by RFC 8996 (2021).
Strengths
- None that justify enabling them today
Weaknesses and known attacks
- POODLE (2014): padding oracle against SSL 3.0 CBC.
- BEAST (2011): chosen-plaintext attack on TLS 1.0 CBC with predictable IVs.
- Downgrade attacks that force a connection to the weakest common version.
- Reliance on RC4, MD5 and SHA-1.
Use it for
- Nothing; disable them and test with a TLS scanner
Don't use it for
- Any connection
Exam tip
'SSL certificate' is common slang, but the protocol in use should be TLS 1.2 or 1.3. POODLE = SSL 3.0; BEAST = TLS 1.0. The fix for both is to disable the old version.