Network

Looks like nokia phonet protocol (but i’m not sure), are there some tools for analysis ? Or only manual ?

The attached RFC for the chall was writen by a Nokia employee so you might be right.
I guess Wireshark and Scapy are a great way to start.

Any other hints for this challenge ?

Hi everyone,

I read the file entirely and found a way to start on the pcap file.
I see a packet that is bigger than the others on Wireshark.
Length 126 instead of 31 or 40 for all the others.

Nevertheless, I never see something that relates to sms in the pcap file.

Do you know how I could be able to find the url scheme sms on the pcap file.

There is indeed some sort of communication between the modem and the "unknown" as the frame 87 comes from the modem and the 88 comes from the "unknown".
Nevertheless, I don’t see how I could go any further. 😕

Thanks for your help.

Ok, I got it.

It is an Sms, so the data stream is an encoded SMS message.
Sms is a 7-bit encoded message from the RFC.

You should find something to decode a 7-bit encode message on the internet (or Github as a quick python script).

@Shostarsson
You’re on right way, continue finding the hex data, try to decode it.

Hello,
I passed this challenge but I search for informations about how decrypt data with wireshark. Did someone has found how to use a gsm plugin with wireshark?

There is indeed a wireshark plugin https://git.ring0.de/sre/isi-wireshark-plugin, but I haven’t tested it.
Also per https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=11676 this protocol should already be handled by wireshark since 2015 (?)