A method, system and product for determining a characterization of a terminal within a binary code, based on influences of the terminal. Based on the characterization of the terminal, the terminal is determined to be potentially affected by external input that is inputted to a device executing the binary code. A propagation path that indicates a reachability of the terminal within the binary code is determined. A code patch associated with a functionality of at least a portion of the binary code and with the propagation path of the terminal is located in the binary code. The code patch can be executed independently from the binary code. The code patch is extracted from the binary code for testing, and an emulation of the code patch is generated to enable fuzz testing of the emulation, whereby the code patch is tested independently.