This is a quick email to bring your attention to a recently publicised OpenSSL security vulnerability known as "Heartbleed". The Common Vulnerabilities and Exposures list has assigned CVE-2014-0160 for this issue.
The vulnerability is currently being exploited in the wild on a small scale.
The vulnerability is a memory disclosure bug. That is, a malicious user can send a trigger packet to an HTTPS service with a vulnerable OpenSSL instance, and the server will respond with the raw memory contents of the HTTP server (such as Apache) or OpenSSL.
Am I vulnerable?
Only OpenSSL versions 1.0.1, 1.0.1a through to 1.0.1f are vulnerable. Version 1.0.1 was released March 2012. Version 1.0.1g was released today and is immune (many distributions have not yet released updates, but they should become available within 24 hours). Versions prior to 1.0.1, such as 1.0.0 and the 0.9.x variants do not include this specific vulnerability.
You can check what version you have by running openssl with the version switch:
# openssl version
OpenSSL 1.0.1f 6 Jan 2014 (vulnerable)
This bug is specific to OpenSSL only. Microsoft products may not be affected, however Windows products which utilise OpenSSL may be affected. Most Linux and unix variants utilise OpenSSL.
It is worth determining what risks this presents to your organisation. As the private key can be compromised and traffic decrypted, consider whether a new private key should be issued and signed by CA (once the server has been patched).