Thought I’d take a few moments and talk about the latest Internet-wide vulnerability called, of all things, POODLE.
But first a little background. Back when the Internet was first created, there was no security. None. Everyone trusted everyone else and the idea that they’d need to keep things secure wasn’t an issue. That worked fine when it was just a couple of universities and a few defense contractors. But the Internet grew and the users connected to it became diverse. And my “diverse” I mean filled with both good and bad guys.
Perhaps you’d expect the folks who created the Internet would go back to the drawing board and redesign things with security built in, but that’s not how those guys think. The Internet was designed to be as simple as possible. If you needed something more than just the ability to move bits from one place to another, you had to create a layer on top of the existing network that did what you needed. That’s why there are things like HTTP (the basis of the World Wide Web), it handles all the special things you need to display web pages that aren’t already there.
The software that the Internet runs on is called TCP/IP. It stands for Transmission Control Protocol/Internet Protocol. TCP handles things like making sure the bits you send somewhere actually get there and in the right order while IP helps tie together different smaller networks so they all seem like one big network. TCP/IP doesn’t care if your bits are from a web page or an email or an MP3 file, it just makes sure it gets to where it’s supposed to go.
That’s why if you want to do cool things like the WWW or email, you have to add software to do it that works with TCP/IP. That’s why if you want to send those bits in a way that no one but your intended recipient can read, you need to add a security layer to TCP/IP. The first attempt to do that is called Secure Sockets Layer or SSL.
SSL uses encryption to achieve that security. And that’s what’s wrong with it and why POODLE is in the news. SSL has gone through three revisions. Version 1 was never really used, version 2 was for a while but it was quickly replaced by version 3. Version 3 hung in there for years but you have to understand that it was designed in the 1990s. The encryption it uses is easily broken. That makes it unsafe to use and it was replaced by Transport Layer Security, or TLS.
TLS has much better encryption, although it’s had to go through multiple versions as well to keep up. Pretty much every computer and operating system supports TLS so you’d think the problem would be gone. Well, you’d think that but unfortunately, many systems still support SSL version 3 as a backup in case something happens with TLS. So instead of getting an error about not being able to securely connect, your computer quietly drops into what is an effectively insecure connection without telling you. So you think you’re secure, but you’re not.
What’s worse, a bad guy can listen in to connections being made and interfere in such a way to force this drop into SSLv3 and read your communications (sometimes called a Man-in-the-Middle attack). All of this is possible because most computers and servers still support SSLv3 “just in case”. Sure it’s broken and not secure but hey, you never know.
POODLE, which stands for Padding Oracle On Downgraded Legacy Encryption, is the official name for that attack. It’s been around for a very long time and really knowing if anyone’s used it or not is difficult. Security folks take the easy route and assume it has. Still, it’s possible to defend against it for the most part.
The majority of network traffic is probably the result of your web browser. Luckily, browsers like Firefox and Internet Explorer can have SSLv3 shut off entirely right now. Both browsers will have new versions with SSLv3 removed eventually so you should look for those updates. Chrome does not allow you to turn SSLv3 off from its settings menu so it will require a new version.
Since so many servers still support SSLv3, they will have to be updated as well. Google is proposing a change for servers to implement but it remains to be seen if everyone is going to use that or adopt something else. The good news is you don’t have to wait as long as you can turn SSLv3 off in your computer/smartphone/tablet etc.
Here are some info links on turning off SSLv3 in various web browsers:
Internet Explorer – Note: Only for version 7 and higher. Version 6 does not support TLS and you shouldn’t be using it.
Chrome – Note: More complicated than the other two.
I should note there’s small probability that if you turn off SSLv3 you might see some connection issues with certain web sites. It won’t be the Googles or Facebooks but more likely smaller sites that haven’t kept up with the times. It’s up to you to decide if viewing them is important enough to turn SSLv3 back on. If you do that, don’t do it while connected to public WiFi. The likelihood of a bad guy who’s looking to take advantage of POODLE also being connected to that access point is quite high.
If you want a nice “ones and zeroes” description of the vulnerability How POODLE Happened is pretty good.