WPA2 Security Flaw Puts Almost Every Wi-Fi Device at Risk of Hijack, Eavesdropping (zdnet.com)

A security protocol at the heart of most modern Wi-Fi devices, including computers, phones, and routers, has been broken, putting almost every wireless-enabled device at risk of attack. From a report: The bug, known as "KRACK" for Key Reinstallation Attack, exposes a fundamental flaw in WPA2, a common protocol used in securing most modern wireless networks. Mathy Vanhoef, a computer security academic, who found the flaw, said the weakness lies in the protocol's four-way handshake, which securely allows new devices with a pre-shared password to join the network. That weakness can, at its worst, allow an attacker to decrypt network traffic from a WPA2-enabled device, hijack connections, and inject content into the traffic stream. In other words: hackers can eavesdrop on your network traffic. The bug represents a complete breakdown of the WPA2 protocol, for both personal and enterprise devices -- putting every supported device at risk. "If your device supports Wi-Fi, it is most likely affected," said Vanhoef, on his website. News of the vulnerability was later confirmed on Monday by US Homeland Security's cyber-emergency unit US-CERT, which about two months ago had confidentially warned vendors and experts of the bug, ZDNet has learned.

Comments

Finally!

[khandom08]

Public announcement from Mathy Vanhoef is https://www.krackattacks.com/ and his research paper can be found https://papers.mathyvanhoef.co....

So which is it?

[Solandri]

the weakness lies in the protocol's four-way handshake, which securely allows new devices with a pre-shared password to join the network. [...] The bug represents a complete breakdown of the WPA2 protocol, for both personal and enterprise devices

WPA2 enterprise doesn't use a pre-shared key. So which is it? Does the weakness lie with pre-shared key passwords? Or something else which also affects WPA2 enterprise?

Ah, here we go. The answer is "it's complicated." I'm reading through it right now, but as a PSA:

• Here's the original paper on the attack
• Here's CERT's page on the attack
• Here's ICASI's (mostly useless) page on the attack

In the future can we link to original source articles or responses by authoritative organizations, instead of trade rags?

TLDR; Replay packet 3

[complete loony]

Replay packet 3 in the 4 way handshake, and the client will encrypt two different payloads with the same key and nonce. A big mistake with most encryption methods.

Worse, linux wpa_supplicant nulls out the key memory but still processes the replayed packet, causing the client to use a known (zero) key.

Re:How serious is this? How exploitable is it?

[140Mandak262Jamuna]

Not remotely exploitable. So it is not going to infect like the heartbleed or shellshock

Need to build a device with the special software and come within range of a router to sniff the keys. Then can eaves drop on communication between router and client.

It will take a day at least to build it and then one has to come physically close.

Vulnerable places will be coffee shops, malls, airports etc. Stores that use wi-fi between cash registers and router would be the primary target. BTW Target had security cameras and cash registers talking to the same router using same passwords. If I remember it correctly.

Re:How serious is this? How exploitable is it?

[khandom08]

No it is an attack on both. Though it appears that patched clients would be safe while connected to an upatched AP.

Re:How serious is this? How exploitable is it?

[Junta]

And vice versa, a patched AP can prevent a client from breaking. One or the other side needs to prevent it, but either side by itself is sufficient.