I am interested in starting to decode and understand some proprietary network traffic, sent from apps on various devices, such as my TV, game consoles, phones etc.Most of the things I want to look at, seems to be using UDP to send proprietary protocol traffic.I've spent some time in Wireshark analyzing traffic, and now the next stage is to attempt modifying messages and looking at results. This is where I have run into trouble. I attempted to use my Windows laptop as a MitM, bridging my 2 Ethernet connections (one to device and one to router). However, it seemed I was completely unable to spoof traffic from the device. Since UDP is very spoof able, I was not sure what is going wrong.What is the best way to do this, and is there a framework/toolkit in place to help facilitate this type of research?
Getting started with reversing device network traffic
networking
As shown here you can use Scapy to capture and/or spoof packets, while you are doing that make sure you computed checksums right. You can use Wireshark to check headers. Most convenient way is capturing incoming traffic and changing data and checksum.