Decoding BlazorPack

This post explains how to analyze and tamper with server-side Blazor (BlazorPack) WebSocket traffic by using Mallet instead of BurpSuite, which lacks support for aggregating continuation frames. It outlines a Netty-based pipeline (SOCKS, SSL sniffing, HTTP/WebSocket upgrade, Protobuf varint framing, and MessagePack decoding/encoding), provides Groovy scripts for dynamically inserting codecs after the initial JSON negotiation, and references required libraries—enabling researchers to convert opaque binary streams into readable, modifiable objects.