SSL
Secure Sockets Layer — deprecatedSSL is what TLS used to be called. Netscape shipped it in 1995, the IETF took it over and renamed version 3.1 to TLS 1.0, and every SSL version has since been broken and formally prohibited. The name survives everywhere — but nothing you use today is actually SSL.
SSL is the retired ancestor of TLS — the word is still used everywhere, and the protocol itself must never be enabled.
How it works
No handshake protection and a weak MAC — prohibited outright by RFC 6176.
POODLE exploited its CBC padding; RFC 7568 prohibited it in 2015.
“SSL certificate”, OpenSSL, ssl_protocols — the word outlived the thing by decades.
If a service still negotiates SSL 3.0 it is not merely old, it is decryptable by a patient attacker on the path. The right reading of “SSL” in any modern document is simply “TLS”.
What SSL does, step by step
SSL 2.0 shipped in 1995 to make web commerce possible; 3.0 followed a year later as a redesign.
SSL 3.1 was standardised as TLS 1.0 in 1999 — a small change of protocol and a large change of name.
Weak MACs, downgrade attacks and finally POODLE in 2014 left nothing salvageable.
Certificates, libraries and config directives still say SSL while speaking nothing but TLS.
In cybersecurity
There is no configuration in which SSL is acceptable: both versions are cryptographically broken, and leaving them enabled lets an attacker downgrade a modern client to them.
Padding oracle on downgraded legacy encryption — the attack that finished SSL 3.0 in 2014.
A server still offering SSL 2.0 anywhere could be used to decrypt its own modern TLS sessions.
Clients that retried with older versions on failure handed attackers the choice of protocol.
Set the minimum version to TLS 1.2; do not rely on defaults in old software.
A scan showing SSLv3 in the accepted list is a finding, whether or not anything uses it.
PCI DSS and most baselines have prohibited SSL entirely for years.