Last week, it was revealed that a commonly used piece of open source software, OpenSSL, was vulnerable to attack. There is a great short cartoon that explains how the vulnerability works here: http://grahamcluley.com/2014/04/heartbleed-bug-explained/.
The good news is no SFAR listing or membership data was affected by this vulnerability, and no action was required or taken with regard to the SFARMLS. Your usernames and passwords were never at risk.
Accounts with many common software companies used by REALTORS®, could however, be vulnerable. You can read more about which Internet companies were vulnerable on Mashable (http://mashable.com/2014/04/09/heartbleed-bug-websites-affected/) but the short ‘big hit list’ includes: Google, Facebook, Instagram, Pintrest, Tumblr, Twitter, Yahoo, Box.com, Etsy, Flickr, and DropBox.
Please make sure you change your passwords if you are concerned about the safety of your information and want to be certain that you are not vulnerable to identity theft or misuse of sensitive data, particularly data related to your clients. If you use services that also have 2 factor authentication (http://en.wikipedia.org/wiki/Two-step_verification), you should consider enabling that feature for an added level of security.