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ronin-fuzzer is a Ruby library and CLI for generating, mutating, and fuzzing data. The goal of ronin-fuzzer is to be both easy to use and highly customizable.


  • Provides a Fuzzer class for incremental substitution fuzzing of data.
  • Provides a Mutator class for combinatorial substitution mutation of data.
  • Provides methods for enumerating over common "bad strings".
  • Provides core extension methods to Ruby's String class.


Fuzzes an input file and generates output bad files for testing:

$ ronin-fuzzer fuzz -i http_request.txt -o bad.txt -r unix_path:bad_strings



$ gem install ronin-fuzzer


gem 'ronin-fuzzer', '~> 0.1'


gem.add_dependency 'ronin-fuzzer', '~> 0.1'


  1. Fork It!
  2. Clone It!
  3. cd ronin-fuzzer/
  4. bundle install
  5. git checkout -b my_feature
  6. Code It!
  7. bundle exec rake spec
  8. git push origin my_feature


Copyright (c) 2006-2023 Hal Brodigan (

This file is part of ronin-fuzzer.

ronin-fuzzer is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

ronin-fuzzer is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with ronin-fuzzer. If not, see