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KleeFL - Seeding Fuzzers With Symbolic Execution

HowTo ...

Prepare dependencies or simply grab the provisioned vagrant box

http://bit.ly/download_kleefl_box

Vagrant box

1. Download the package.box file.
2. Install vagrant (if not already installed) sudo apt-get install vagrant
3. Add the package.box file to vagrant vagrant box add kleefl package.box
4. Initialize the vagrant box (kleefl) vagrant init kleefl
5. Bring the box up vagrant up
6. SSH to the box vagrant ssh

Setup a project structure like this:

mkdir project_xyz
cd project_xyz
python /vagrant/tools/kleefl_init -- sets up two directories called 'klee' and 'fuzz' in your root project directory

Select your source code, e.g.:

cp -r /vagrant/example source

Build source using wllvm & afl-clang

cd source
/vagrant/tools/kleefl_build_make make

Choose & set up a target binary for evaluation

./kleefl_pick target_binary_name

Generate the test cases for AFL (KLEE symbolic execution)

The previous script will add a file called app.bc within the klee directory.
Change into the klee folder and run:
./run_klee.sh

Prepare klee's findings for afl-fuzz

python /vagrant/tools/kleefl_prepare_afl

Finally: Fuzz, fuzz, fuzz!

../fuzz/run_afl.sh

Analyze findings

./kleefl_crash_inspector fuzz/out
(fuzz/out is the afl sync dir, report saved by default in vagrant shared dir /vagrant/crash_report/)

Analyze coverage & generate report

python kleefl_cov_inspector {make, binary fuzz/sync_dir}
zcov genhtml coverage.zcov cov_report

Further details can found in the project report or check out our beautiful USENIX poster