Post by @nullagent@partyon.xyz

2025-08-20 01:37 UTC

This segment of meshtastic's DEFCON post are sadly not correct. I can't tell you why how exactly the firmware and phone app work but I can tell you that if you are near someone PKI spoofing it absolutely does replace the users private key on BOTH the app and the firmware. The only pub keys that are pinned are your favorites list. It doesn't matter what -type- of AES is used after the public key is replaced you're already MITMd. https://meshtastic.org/blog/that-one-time-at-defcon #privacy #cybersecurity #meshtastic

Replies (3)

@nullagent@partyon.xyz 2025-08-20 01:44

So to hopefully make it more clear, I wrote a CLI tool which can recover the decryption parameters for DM conversations. It basically does everything but the final AES-CCM decryption. Turns out there's something funky with the meshtastic AES-CCM implementation and I can't seem to fully decrypt using an openssl based library. This does not mean DMs are any safer, just that I haven't taken the time to crosscompile the MT/arduino AES routines to x86 yet. https://github.com/datapartyjs/meshmarauder/blob/main/bin/mitm-dm #meshtastic

Open ##3059398
@Bokonon@defcon.social 2025-08-20 14:42

@nullagent@partyon.xyz so just out of curiosity, what's the reasoning behind posting vulnerabilities like this publicly and not doing a responsible/coordinated vulnerability disclosure? After the blog post they made, it was clear you had their attention already. Just seems a bit hostile towards the users to release such things publicly before allowing for a patch to be made available. Appreciate your work otherwise. The Meshtastic community has been begging for more eyes on it from security researchers to help harden things up.

Open ##3059418
@Bokonon@defcon.social 2025-08-20 21:32

@nullagent@partyon.xyz so.... No comment on the responsible disclosure then?

Open ##3059422