AFL++ FrameShift Prototype

This repository is a prototype implementation of FrameShift, on top of AFL++ (v4.21c).

The core algorithm and implementation is in src/afl-fuzz-frameshift.c.

The main changes are:

• A FrameShift mode which is enabled with AFL_FRAMESHIFT_ENABLED=1
• The queue_entry structure is extended with a new fs_meta_t *fs_meta field pointing to the learned relation(s) for the input, and a u8 fs_status indicator.
• When a new input is processed for the first time inside fuzz_one_original, it will run the frameshift_stage on the input to try to learn relations.
• havoc and splice mutations are tracked and before running the input, the new relation values (if any) are re-serialized into the input.

Original README.md below:

---

American Fuzzy Lop plus plus (AFL++)

Release version: 4.21c

GitHub version: 4.21c

Repository: https://github.com/AFLplusplus/AFLplusplus

AFL++ is maintained by:

• Marc "van Hauser" Heuse mh@mh-sec.de
• Dominik Maier mail@dmnk.co
• Andrea Fioraldi andreafioraldi@gmail.com
• Heiko "hexcoder-" Eissfeldt heiko.eissfeldt@hexco.de
• frida_mode is maintained by @Worksbutnottested
• Documentation: Jana Aydinbas jana.aydinbas@gmail.com

Originally developed by Michal "lcamtuf" Zalewski.

AFL++ is a superior fork to Google's AFL - more speed, more and better mutations, more and better instrumentation, custom module support, etc.

You are free to copy, modify, and distribute AFL++ with attribution under the terms of the Apache-2.0 License. See the LICENSE for details.

Getting started

Here is some information to get you started:

• For an overview of the AFL++ documentation and a very helpful graphical guide, please visit docs/README.md.
• To get you started with tutorials, go to docs/tutorials.md.
• For releases, see the Releases tab and branches. The best branches to use are, however, stable or dev - depending on your risk appetite. Also take a look at the list of important changes in AFL++ and the list of features.
• If you want to use AFL++ for your academic work, check the papers page on the website.
• To cite our work, look at the Cite section.
• For comparisons, use the fuzzbench aflplusplus setup, or use afl-clang-fast with AFL_LLVM_CMPLOG=1. You can find the aflplusplus default configuration on Google's fuzzbench.

Building and installing AFL++

To have AFL++ easily available with everything compiled, pull the image directly from the Docker Hub (available for both x86_64 and arm64):

docker pull aflplusplus/aflplusplus
docker run -ti -v /location/of/your/target:/src aflplusplus/aflplusplus

This image is automatically published when a push to the stable branch happens (see branches). If you use the command above, you will find your target source code in /src in the container.

Note: you can also pull aflplusplus/aflplusplus:dev which is the most current development state of AFL++.

To build AFL++ yourself - which we recommend - continue at docs/INSTALL.md.

Quick start: Fuzzing with AFL++

NOTE: Before you start, please read about the common sense risks of fuzzing.

This is a quick start for fuzzing targets with the source code available. To read about the process in detail, see docs/fuzzing_in_depth.md.

To learn about fuzzing other targets, see:

• Binary-only targets: docs/fuzzing_binary-only_targets.md
• Network services: docs/best_practices.md#fuzzing-a-network-service
• GUI programs: docs/best_practices.md#fuzzing-a-gui-program

Step-by-step quick start:

1. Compile the program or library to be fuzzed using afl-cc. A common way to do this would be:

   CC=/path/to/afl-cc CXX=/path/to/afl-c++ ./configure --disable-shared
   make clean all
   

2. Get a small but valid input file that makes sense to the program. When fuzzing verbose syntax (SQL, HTTP, etc.), create a dictionary as described in dictionaries/README.md, too.

3. If the program reads from stdin, run afl-fuzz like so:

   ./afl-fuzz -i seeds_dir -o output_dir -- \
   /path/to/tested/program [...program's cmdline...]
   

   To add a dictionary, add -x /path/to/dictionary.txt to afl-fuzz.

   If the program takes input from a file, you can put @@ in the program's command line; AFL++ will put an auto-generated file name in there for you.

4. Investigate anything shown in red in the fuzzer UI by promptly consulting docs/afl-fuzz_approach.md#understanding-the-status-screen.

5. You will find found crashes and hangs in the subdirectories crashes/ and hangs/ in the -o output_dir directory. You can replay the crashes by feeding them to the target, e.g. if your target is using stdin:

   cat output_dir/crashes/id:000000,* | /path/to/tested/program [...program's cmdline...]
   

   You can generate cores or use gdb directly to follow up the crashes.

6. We cannot stress this enough - if you want to fuzz effectively, read the docs/fuzzing_in_depth.md document!

Contact

Questions? Concerns? Bug reports?

• The contributors can be reached via (e.g., by creating an issue): https://github.com/AFLplusplus/AFLplusplus.
• Take a look at our FAQ. If you find an interesting or important question missing, submit it via https://github.com/AFLplusplus/AFLplusplus/discussions.
• Best: join the Awesome Fuzzing Discord server.
• There is a (not really used) mailing list for the AFL/AFL++ project (browse archive). To compare notes with other users or to get notified about major new features, send an email to afl-users+subscribe@googlegroups.com, but note that this is not managed by us.

Branches

The following branches exist:

• release: the latest release
• stable/trunk: stable state of AFL++ - it is synced from dev from time to time when we are satisfied with its stability
• dev: development state of AFL++ - bleeding edge and you might catch a checkout which does not compile or has a bug. We only accept PRs (pull requests) for the 'dev' branch!
• (any other): experimental branches to work on specific features or testing new functionality or changes.

Help wanted

We have several ideas we would like to see in AFL++ to make it even better. However, we already work on so many things that we do not have the time for all the big ideas.

This can be your way to support and contribute to AFL++ - extend it to do something cool.

For everyone who wants to contribute (and send pull requests), please read our contributing guidelines before you submit.

Special thanks

Many of the improvements to the original AFL and AFL++ wouldn't be possible without feedback, bug reports, or patches from our contributors.

Thank you! (For people sending pull requests - please add yourself to this list :-)

List of contributors

 Jann Horn Hanno Boeck
Felix Groebert Jakub Wilk
Richard W. M. Jones Alexander Cherepanov
Tom Ritter Hovik Manucharyan
Sebastian Roschke Eberhard Mattes
Padraig Brady Ben Laurie
@dronesec Luca Barbato
Tobias Ospelt Thomas Jarosch
Martin Carpenter Mudge Zatko
Joe Zbiciak Ryan Govostes
Michael Rash William Robinet
Jonathan Gray Filipe Cabecinhas
Nico Weber Jodie Cunningham
Andrew Griffiths Parker Thompson
Jonathan Neuschaefer Tyler Nighswander
Ben Nagy Samir Aguiar
Aidan Thornton Aleksandar Nikolich
Sam Hakim Laszlo Szekeres
David A. Wheeler Turo Lamminen
Andreas Stieger Richard Godbee
Louis Dassy teor2345
Alex Moneger Dmitry Vyukov
Keegan McAllister Kostya Serebryany
Richo Healey Martijn Bogaard
rc0r Jonathan Foote
Christian Holler Dominique Pelle
Jacek Wielemborek Leo Barnes
Jeremy Barnes Jeff Trull
Guillaume Endignoux ilovezfs
Daniel Godas-Lopez Franjo Ivancic
Austin Seipp Daniel Komaromy
Daniel Binderman Jonathan Metzman
Vegard Nossum Jan Kneschke
Kurt Roeckx Marcel Boehme
Van-Thuan Pham Abhik Roychoudhury
Joshua J. Drake Toby Hutton
Rene Freingruber Sergey Davidoff
Sami Liedes Craig Young
Andrzej Jackowski Daniel Hodson
Nathan Voss Dominik Maier
Andrea Biondo Vincent Le Garrec
Khaled Yakdan Kuang-che Wu
Josephine Calliotte Konrad Welc
Thomas Rooijakkers David Carlier
Ruben ten Hove Joey Jiao
fuzzah @intrigus-lgtm
Yaakov Saxon Sergej Schumilo

Cite

If you use AFL++ in scientific work, consider citing our paper presented at WOOT'20:

Andrea Fioraldi, Dominik Maier, Heiko Eißfeldt, and Marc Heuse. “AFL++: Combining incremental steps of fuzzing research”. In 14th USENIX Workshop on Offensive Technologies (WOOT 20). USENIX Association, Aug. 2020.

BibTeX

@inproceedings {AFLplusplus-Woot20,
author = {Andrea Fioraldi and Dominik Maier and Heiko Ei{\ss}feldt and Marc Heuse},
title = {{AFL++}: Combining Incremental Steps of Fuzzing Research},
booktitle = {14th {USENIX} Workshop on Offensive Technologies ({WOOT} 20)},
year = {2020},
publisher = {{USENIX} Association},
month = aug,
}