Some operating system distributions that have shipped with potentially vulnerable OpenSSL version:
Debian Wheezy (stable), OpenSSL 1.0.1e-2+deb7u4
Ubuntu 12.04.4 LTS, OpenSSL 1.0.1-4ubuntu5.11
CentOS 6.5, OpenSSL 1.0.1e-15
Fedora 18, OpenSSL 1.0.1e-4
OpenBSD 5.3 (OpenSSL 1.0.1c 10 May 2012) and 5.4 (OpenSSL 1.0.1c 10 May 2012)
FreeBSD 10.0 - OpenSSL 1.0.1e 11 Feb 2013
NetBSD 5.0.2 (OpenSSL 1.0.1e)
OpenSUSE 12.2 (OpenSSL 1.0.1c)
Operating system distribution with versions that are not vulnerable:
Debian Squeeze (oldstable), OpenSSL 0.9.8o-4squeeze14
SUSE Linux Enterprise Server
FreeBSD 8.4 - OpenSSL 0.9.8y 5 Feb 2013
FreeBSD 9.2 - OpenSSL 0.9.8y 5 Feb 2013
FreeBSD Ports - OpenSSL 1.0.1g (At 7 Apr 21:46:40 2014 UTC)
How can OpenSSL be fixed?
Even though the actual code fix may appear trivial, OpenSSL team is the expert in fixing it properly so latest fixed version 1.0.1g or newer should be used. If this is not possible software developers can recompile OpenSSL with the handshake removed from the code by compile time option -DOPENSSL_NO_HEARTBEATS
Can I detect if someone has exploited this against me?
Exploitation of this bug leaves no traces of anything abnormal happening to the logs.
http://heartbleed.com/