AFL Runner
AFL_Runner is a modern CLI tool designed to streamline running efficient multi-core AFLPlusPlus campaigns. The default configuration is based on the section Using multiple cores of the official documentation.
Getting Started π
Currently, this tool should work on all *NIX flavor operating-systems.
Prerequisites
- Rust toolchain v1.78.0+ π¦
- AFLPlusPlus
- pgrep
- TMUX || screen (Optional)
Installation
You can compile AFL_Runner yourself...:
...or install directly via crates.io:
Features β¨
AFL_Runner allows you to set the most necessary AFLPlusplus flags and mimics the AFLplusplus syntax for these options:
-
Supported AFLplusplus flags:
- Corpus directory
- Output directory
- Dictionary file/directory
- Custom
afl-fuzzbinary path for all instances - Supply arguments to target binary (including @@)
- Amount of runner commands to generate
- Support for *SAN, CMPLOG, CMPCOV binaries
-
Other features:
-
Tmuxorscreenoption to automatically create an appropriate layout for all runners - TUI
- Provide a configuration file via
--configto make sharing/storing per project configurations easier- Automatically read out a configuration named
aflr_cfg.tomlin theCWDwhen no--configwas supplied
- Automatically read out a configuration named
- Mode:
default(vanilla AFL++),multiple-cores(Ref.), andci-fuzzing(Ref.)! - Deterministic command generation and AFL++ with seeding
-
Note: Arguments supplied over the command-line take precedence over any configuration file options.
What is not? β
AFL_Runner aims to be a plug & play solution for when you're at a stage of fuzzing campaign where all that is left is running a multi-core setup.
So, this tool is not (yet) a helper for:
- Compiling a target in multiple flavors
- Preparing a good initial seed corpus
- Providing a decent dictionary to boost code-coverage
- Debugging a fuzzing campaign
Roadmap πΊοΈ
- Add remote option π
- Native integration for statsd
- Add more configuration options
- Add more sensible defaults for other options
- Full modularity to cater to very specialized fuzzing campaigns
- Allow AFLPlusPlus forks to be used on some amount of runners
Usage Example π‘
Here's an example of generating AFL++ commands with AFL_Runner:

Note: Supplying the *SAN, CMPLOG, or CMPCOV binaries is optional and if omitted all invocations just contain the (mandatory) instrumented target instead.
Showcase π₯
AFL_Runner also includes a terminal user interface (TUI) for monitoring the fuzzing campaign progress.
The following demo can be found in examples/ and can be build locally by running cargo make from the root directory of the project.
The example builds a recent version of libxml2 four times with different compile-time instrumentations:
- plain AFL++ instrumentation
- Address-Sanitizer (ASan)
- CMPCOV, and
- CMPLOG.
Afterwards, the necessary commands for 16 instances are being generated, which then are executed in a dedicated TMUX session. Finally, a custom TUI offered by AFL Runner is tracking the progress of the fuzzing campaign in a centralized space:

Note: The TUI can be used as a full replacement for afl-whatsup by using afl_runner tui <afl_output_dir>!
Contributing π€
Contributions are welcome! Please feel free to submit a pull request or open an issue for any bugs, feature requests, or improvements. Any other support is also more than welcome :). Feel to reach out on X or BSKY.
License π
This project is licensed under the Apache License. See the LICENSE file for details.