We would like to remind everyone to make sure that your systems are currently supported by your Linux vendor or are receiving security updates some other way. If you haven't bothered to update your system or configure automatic updates, then now would be a good time to start.
Note:Standard releases are supported for 18 months. Enterprise grades (LTS) are supported for 3 years on desktop 5 years on server
Unsupported: Redhat Linux
(RHL, not RHEL), see http://www.redhat.com/security/updates/eol/
Supported: Red Hat Enterprise Linux 4, 5 and 6. The End of Production Phase 3 for RHEL5 is March 31st 2017 and for RHEL6 November 30 2020, see the Red Hat Enterprise Linux Life Cycle
openSUSE Life Cycles
Commercial SuSE Distributions
For those distros not listed, please take a minute and check with your vendors website. Remember that keeping your system updated with security patches is one of the most effective measures you can take to keep from getting compromised.