If you applied Microsoft’s security updates, you’re safe from KRACK

Linux and Android appear to be more susceptible, because attackers can force network decryption on clients in seconds with little effort.


Despite the severity of the flaw, it is rather hard to implement.

The internet’s never been completely safe, but now it’s your Wi-Fi’s fault. The new attack works by injecting a forged message 1, with the same ANonce as used in the original message 1, before forwarding the retransmitted message 3 to the victim.

This is because Android and Linux use the same Wi-Fi client software, known as wpa_supplicant.

You may also see an option with the suffix ‘-PSK’ which is short for Pre-Shared-Key or Personal Shared Key.

A Belgian academic researcher has uncovered a flaw in the protocol that secures most Wi-Fi transmissions that could allow attackers to listen in on users’ communications.

“We discovered serious weaknesses in WPA2, a protocol that secures all modern protected Wi-Fi networks”.

Although wireless routers are rarely updated, it’s important to install the patches for your other devices as and when they become available to ensure security on other networks warn the researchers. Vanhoef said that if your device substantiates Wi-Fi it is most likely contrived. Rather, it’s in the implementation. That key is unique to that connection, and that device.

Temporal Key Integrity Protocol (TKIP) is now also being phased out, but unlike WEP is still seen in most modern routers. A flaw in WPA2 allows a nonce to be (or forced to be) repeated, thus allowing an attacker to extract the WPA2 session key and compromise all traffic for that session.

It isn’t often we hear of a vulnerability that could potentially affect every device you own, but a new type of attack being detailed today could very well do that. In such cases, the encryption between the router and client device will be completely broken. This means that even if you visit a HTTPS link, sslstrip will remove all encryption data in the request and you will visit a HTTP version of the website. HTTPS requests can not be viewed in WireShark as they are encrypted, but HTTP is easily read by an attacker. “As a result, now 31.2 percent of Android devices are vulnerable to this exceptionally devastating variant of our attack”. Vanhoef manages to steal the user’s Match.com password and username.

The attack was discovered by Mathy Vanhoef of the imec-DistriNet research group.

Naturally, this ability extends to TCP SYN packets, making it possible for attackers to hijack TCP connections, in functionally the same way attackers inject data on unprotected Wi-Fi networks. That key should only be sent once, but according Vanhoef, it will be resent again if the third message in the four-way handshake is not correct.

Sadly, we still don’t have WPA3, but any possible fix for the KRACK attack would be backward-compatible with previous WPA implementations.


However, it may be hard to update some older Wi-Fi routers. Aside from waiting for a proper update, there isn’t much users can do to protect themselves. The organisation CERT/CC also disseminated news of the vulnerability to vendors on 28th August so at this stage its unlikely your router manufacturer has not received the news.

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