Poor man's WiFi jamming

Sometimes it might be interesting to saturate a particular WiFi channel with user traffic, but you don’t have any WiFi adapter under the hood and you have only a regular Macbook with MacOS.

Hopefully a couple of useful tricks could be used :

  • create an ad-hoc network of your choice (2.4Ghz or 5Ghz) and add some static IP

  • send some broadcast traffic on that IP range with a large size, to avoid frames to be acknowledged at MAC level, while using the largest airtime possible (i.e. robust modulation + actual large frame)

MacOS has a way to create ad-hoc network. After doing this, you can simply allocate an IP address with :

ifconfig en0 add 

(en0 being my adapter on my macbook air)

On channel 44 (5Ghz band) with an HackRF and gqrx, this is what I get with a clean channel (the occasional frame are due to mDNS annoncements of my Mac): Clean channel 44 picture

Then, you can open a shell to run multiple multiple broadcast ping :

for i in {1..100}; do ping -i 0.2 -s 1400 ;  done
# `killall ping` to stop it

The result is pretty self-conclusive : Jammed channel 44 picture

Our channel is now quite loaded with broadcast frames.