In the last few years a number of OpenSSL vulnerabilities have come to light. Heartbleed was a critical one which was exploited in the field. It basically allowed a client to send a malicious heartbeat to the server and get back chunks of server memory – which can contain passwords. It was estimated that two thirds of the servers in the world had the vulnerability. The fix was to upgrade OpenSSL, revoke existing server certs and request new SSL server certs.
Heartbleed previously triggered OpenBSD to fork OpenSSL to LibreSSL and Google to fork OpenSSL to BoringSSL.
Amazon S2N is a TLS/SSL implementation that is 6000 lines of code – so it is small, compact, fast and its correctness can be more easily verified. It uses only crypto functions from openssl and reimplements the SSL layer. This is a healthy direction for IOT and for certification of SSL, for example FIPS. S2N is short for Signal to Noise.
A timing attack was recently identified against it and has since been mitigated.
Note that two factor auth solutions would actually solve the problem presented by Heartbleed. There are several solutions in this area – Authy, Clef, Google Authenticator, Duo, Okta, Oracle Authenticator, ..