Oversimplifying WPA3 And The Dragonfly Handshake

There’s been a lot of talk over the past year or two about the future of WiFi and wireless. Especially of late, most of the focus is on two particular areas: 5G and WiFI 6, otherwise known as 802.11ax. That these two are getting a lot of headlines is not a shock. Those in support of 5G have touted it’s promised speed boosts, and the marketing hype has lead plenty of IT leadership to wonder if the newest generation of wireless could be a WiFi killer (it won’t be). High efficiency WiFi, also known as WiFi 6, is all about better management of the WiFi traffic, which in turn promises to provide end users with better experiences.
Overlooked in all of this? WPA3.

WPA3 first got traction in the aftermath of the Krack vulnerability being revealed, exposing a flaw in WPA2. Considering the age of WPA2, it did have a nice run, but now that it had been compromised, it was time for something new. Enter WPA3.

Right out of the gate, it’s important to say that WPA3 is not a standard or an amendment-things WiFi folks concern themselves with frequently. Instead, WPA3 is actually a certification program. The parameters of this certification program have changed since it was first announced. Initially it was expected to be compliant with four major requirements. However, it now only requires one. In order to achieve WPA3 certification, a device must comply with the settings. In this case, the setting in question is the requirement to support the new dragonfly handshake.

What is the dragonfly handshake, and why is it important?

When you used WPA2 in existing WiFi networks, a curious party could eavesdrop, capture your four way handshake and then, at their leisure, subject the frames to an offline dictionary attack. If your password wasn’t overly complicated, chances are they’d be able to crack it soon enough, at which point they could decrypt the conversations they’d captured-or return and, assuming you hadn’t since changed the password, get a lot more information.

The dragonfly handshake, which is another way of describing Simultaneous Authentication of Equals (SAE), is designed to prevent that attack vector from being useful. To oversimplify this a bit, the idea is that even if a bad actor managed to capture and crack a password, they would be unable to decrypt previously captured frames.

As I understand it, this relates to the concept that the dragonfly handshake is enhancing the well-known four way handshake. The SAE portion of the handshake occurs prior to the four way handshake. During the dragonfly handshake, a new pairwise master key is generated, and this is the PMK used in the subsequent four way handshake.

Keeping with my aim of oversimplifying this, I’ve thought about this addition as a second set of locks on your door. That second lock (and key) changes with each entry, so it’s not as though someone can observe it and make their own copy. In that respect, the addition of SAE to the handshake process means that offline dictionary attacks should, for the most part, become a thing of the past.

Another way that I looked at this, since I just recently completed my CWSP? The idea of Simultaneous Authentication of Equals reminded me a lot of PEAP, the idea of having EAP take place within a secure tunnel. It retains the existing security structure (the four way handshake or EAP, depending on the example) and it adds a layer on top of that which is more secure, thus enhancing what we already know and use.

Like I said, this is really a wicked oversimplification-the entire idea of SAE has a lot more to it. In digging around about it, I found a couple really excellent resources. First is Mathy Van Hoef (https://www.mathyvanhoef.com/). The other was from NC-Expert (https://nc-expert.com/conversations/wpa3-more-secure-wpa2/).

 

 


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