remy🐀Sep 6, 2023

Windows has a buitin protocol that allows for a psuedo-RDP like session over P2P radio, doesn't kick the current user out, and allows for hardware (keyboard, mouse, etc..) input over an RTSP stream called User Input Back Channel.
Is crying in the corner part of your threat model?

I wrote about this feature and technology and included a PCAP here: https://remyhax.xyz/posts/wifi-direct-1/

Once I wrap up my Bluetooth shenanigans this year, WiFi Direct is my next target.

Adventures in Wi-Fi Direct (P2P): Part 1

This blog is far overdue and unfortunately isn’t really a “Part 1”. The truth is, I’ve poked around with Wi-Fi Direct for several months now with mild success and many dead-ends that resulted in learning a lot. The purpose of this blog is to retrace my steps and document some resources before diving into some fun stuff for Part 2.

Show threadwicusrosSep 6, 2023

@_mattata
Nice write up! It can make "war" driving at 8AM so much more fun while in traffic ;-)

Some curious behavior I've noticed.

I'm wondering if this explains something strange I notice with my two Dell laptops, both running Windows 11.

The one laptop is plugged into a Dell dock, powered on and running. There are two external monitors, making for three with the laptop screen. All three are displaying content.

I power the second Dell laptop on. This laptop is not connected to anything except power. During during the start up process the screens on the first Dell that is dock make the strange transition animation like its shrinking - very similar to when you connect an external monitor to Windows 11.

Nothing further happens, but it is a strange behavior that happens ever so often, but only at power up of the second laptop.

Deep down I was wondering if the two devices were communicating somehow, where the docked machine is "discovering" an additional monitor.

I know that the one Dell laptop can cast/project to monitors wirelessly as I've done this with my home TV.

This should make for a nice reason top dust off the ESP.

Show threadremy🐀

@wicusros is the second Dell laptop powered by USB-C and is the dock in question a TB- series?

If so, I likely have your answer and have personally diagnosed the issue in a fleet of laptops many times, but it’s unrelated to wifi direct/miracast

Sep 6, 2023 at 4:19pmWeb
Show threadwicusrosSep 12, 2023

@_mattata the first laptop is powered by two USB-C. The second is on battery or normal powerbrick.

The dock is WD19TB.

Show threadremy🐀Sep 13, 2023

@wicusros EMF interference in USB-C docks is particularly fickle, resulting in the video feed losing sync. Ferrite beads may help.

https://www.youtube.com/watch?v=r-V_Z3bD_PA
https://support.displaylink.com/knowledgebase/articles/738618-display-intermittently-blanking-flickering-or-los

Show threadwicusrosSep 22, 2023
@_mattata Thanks for the advice. One would think that should not be a problem. I guess good quality display port cables with said ferrite beads may help.