I am attempting to fuzz a proprietary binary with no source code that accepts a config file. So the typical use case would be:
./File --config file.config
The config is a bunch of different parameters that are required to run the rest of the program, and runs fine if I run it by itself. Additionally, the config file is within the input directory.
I am attempting to fuzz it utilizing the following command with AFL:
./afl-fuzz -Q -i input/ -o output/ -m 400 ./File --configfile
However, once I run the command, everything looks fine, but as soon as I get to the first iteration of 'havoc', I get an 'odd, check syntax!' error. If I add a @@ at the end, the afl will give me a timeout error. I'm assuming that once afl-fuzz starts to mutate that input file, it breaks the binary, but I'm not sure and I'm not sure what else to try - any ideas? Thanks!