A security flaw, introduced to Mac OS X some months ago leaves users vulnerable to attack. The security hole, created by a programming error, allows Apple's SSL/TLS library to skip verification checks of a server's authenticity when establishing a connection. The flaw affects Macs running OS X 10.9.1.
In short, it's possible for a malicious party to create their own SSL certificate, says it's signed by a valid authority and for the operating system to trust the certificate without actually checking the certificate's credentials. The flaw leaves OS X vulnerable to man in the middle attacks. iOS was recently patched so, assuming users have downloaded and installed the most recent iOS update, those devices are not subject to this flaw.
The issue has been widely reported (see Apple Safari, Mail and more hit by SSL spying bug on OS X, fix 'soon' . The flaw affects applications that use secured connections. That means it's not just a browser issue but hits Mail and other applications like Facetime and iMessage. So it's interesting to see how many security experts are connecting to a public WiFi network at the RSA event with Macs.
A survey of the show floor and the hallways between conference rooms reveals a surprisingly high number of Macs given Apple's market share. Although it's unlikely that they are all connected to the public WiFi offered to conference attendees, it's not unreasonable to suggest most are using the free wireless. In effect, all of these systems are open to attack.
It's hard to know what the best course of action to take is. For many conference attendees (me included) not using their laptop until Apple releases a fix represents a huge productivity problem. But at least one analyst here refuses to turn on his MacBook Pro until a fix is issued.
The good news is that the problem does not affect every application running on a Mac. The specific SSL library that is broken is 55471. So, avoiding applications that use that library is one way of using a Mac that mitigates some risk.
That means switching from Safari to another browser, and avoiding iMessage, Facetime, iBooks, Twitter, Calendar, Software Update, Keynote and other applications that use 55471.
There's no word on when Apple will release an update to OS X that fixes this flaw other than it's coming 'soon'.