WPA2 key exchange broken - KRACK attack

Mathy Vanhoef and Frank Piessens are both decorated security researchers from KU Leuven, Belgium. On an otherwise slow Sunday, 15th October 2017 Alex Hudson dropped a bombshell: Mr. Vanhoef and Mr. Piessens figured out a way to bend the authentication envelope, making WPA2 broken. Authors coined this as a Key Reinstallation AttaCK. Whaat?! Darn!

Looks like the release was planned carefully. OpenBSD had the fix on 1st March 2017. That's over 6 months earlier. Also Microsoft had a whiff of this flaw in the early phase as they managed to release a patch already. The complete vendor list can be seen @ cert.org. Its a sad read, that.

The information is at https://github.com/kristate/krackinfo and contains a very simple message:

Unless a known patch has been applied, assume that all WPA2 enabled Wi-fi devices are vulnerable.

Ok, that sounds really bad. To cut all the FUD and blah blah out, what's the big deal?

• This is a Wi-Fi client attack
  • Explanation: The entire KRACK thing works by spoofing as your router to your client. After the attacker manages to lure your laptop or cell phone into connecting to a fake network, it acts as a man-in-the-middle reading your transmissions.
  • You cannot hide your network information. If you transmit or read transmissions, somebody can read that. That's the bad part about radio transmissions, they travel to everyone.
  • The only way to hide your radio transmissions is to turn Wi-Fi off.
• Anybody attacking YOU needs to be in same physical area than you
  • Explanation: A random guy from The Net cannot attack you. They need to travel to where you are.
• Regardless of what, attacker will not gain your WPA password
  • Explanation: This attack is about fooling your laptop/cell phone/refridgerator to talk to a malicious wireless router. It does not extract your Wi-Fi network password while doing it.
  • So, this is almost as bad as the WEP weakness back in 2001. In that particular incident any random body could just crack their way to your network by figuring out what your password is. And then it was possible to read any captured past or future transmission. KRACK works only forwards, your historical transmissions are safe.
• If you are using TKIP or don't know if you are using it - you're doomed!
  • Explanation: TKIP, or Temporal Key Integrity Protocol is weak anyway. You shouldn't be using that in the first place!
• If you are using Android or Linux - you're most certainly doomed!
  • Explanation: The implementation in Linux (Android is a Linux, you know) is especially flawed! Attacker has easy means of forcing any client to fake router and then force your encryption key to something the attacker can predict, thus being able to read your traffic in real-time or introduce new data packets and spoof them to originating from your Linux/Android. That's bad, really bad!
• If you are not using Linux, and are using AES-encryption - you're doomed!
  • Explanation: Yes, if attacker can lure you to use the faked router, your transmissions can be read.
  • Examples of non-Linux clients include, but are not limited to: Windows, macOS, iOS.
• My router has Linux or I got my router free when I got my Internet connection and I don't know what operating system it has - you're doomed!
  • Explanation: This is not about your router. This is about attacker faking to be your router. Your router won't be attacked, but attacker will spoof traffic to it.
• If a random attacker can read all my traffic and can inject new transmissions spoofing as you, is that bad?
  • Explanation: Yes it is. Attacker can attempt to stop you from using SSL/TLS and there are number of scenarios where that can happen, so all your precious passwords, credit card numbers and other secrets can leak. However, there are number of scenarios where that is not possible. Still, if attacker has your encrypted traffic, other means of decrypting it exist.

As you can see from the above list, there are quite a few scenarios which end you in the 'you're doomed!' -state. So, assume that you are or will be!

The relevant question remains: Is there anything that can be done?
Answer is: Not really

Just wish/pray that your particular vendor releases fixed firmware sometimes soon. Most Android vendors won't.