[mrb]

No, you do not need expensive hardware such as SDR to carry the KRACK attacks. Most plain standard WLAN adapters support AP mode, which is all you need to simulate the rogue network, as demonstrated in the video.

[SadWebDeveloper]

You still need proximity to the client, a powerful SDR will definitely improve reliability on real-life environments.

[twitchyliquid64]

I stand corrected. Rogue AP / MiTM only needs a AP with the ability to send raw packets, gotcha.