KRACK Detector – Detect And Prevent KRACK Attacks In Your Network

KrackKRACK Detector is a Python script to detect possible KRACK attacks against client devices on your network. The script is meant to be run on the Access Point rather than the client devices. It listens on the Wi-Fi interface and waits for duplicate message 3 of the 4-way handshake. It then disconnects the suspected device, preventing it from sending any further sensitive data to the Access Point.

KRACK Detector currently supports Linux Access Points with hostapd. It uses Python 2 for compatibility with older operating systems. No external Python packages are required.


Run as root and pass the Wi-Fi interface as a single argument. It is important to use the actual Wi-Fi interface and not any bridge interface it connects to.

python wlan0

If you do not wish to disconnect suspected devices, use the -n flag

python -n wlan0

Known Issues

Message 3 of the 4-way handshake might be retransmitted even if no attack is perfomed. In such a case the client device will be disconnected from the Wi-Fi network. Some client devices will take some time to re-authenticate themselves, losing the Wi-Fi connection for a few seconds.

What is Krack ?

KRACK attack, now fully disclosed after almost 14 years of exposing our assumed to be encrypted wireless communications, affects today nearly every wireless device out there. Your Android cellular phone, network cameras, robotic vacuum cleaner and even your smart doorbell – all are vulnerable to this mysterious phenomenon that leaves their wireless communication exposed to hijacking, manipulations and in some cases even fully stripped from the encryption that should have kept our data private.


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