RESEARCH | July 30, 2021

Breaking Protocol (Buffers): Reverse Engineering gRPC Binaries

gRPC is an open-source RPC framework from Google which leverages automatic code generation to allow easy integration to a number of languages. Architecturally, it follows the standard seen in many other RPC frameworks: services are defined which determine the available RPCs. It uses HTTP version 2 as its transport, and supports plain HTTP as well as HTTPS for secure communication. Services and messages, which act as the structures passed to and returned by defined RPCs, are defined as protocol buffers. Protocol buffers are a common serialization solution, also designed by Google.