T-Fuzz

T-Fuzz consists of 2 components:

• Fuzzing tool (TFuzz): a fuzzing tool based on program transformation
• Crash Analyzer (CrashAnalyzer): a tool that verifies whether crashes found transformed programs are true bugs in the original program or not (coming soon).

OS support

The current version is tested only on Ubuntu-16.04, while trying to run the code, please use our tested OS.

Prerequisite

T-Fuzz system is built on several opensource tools.

• angr
• shellphish fuzzer
• angr tracer
• radare2 and its python wrapper r2pipe

Installing radare2

$ git clone https://github.com/radare/radare2.git
$ cd radare2
$ ./sys/install.sh

Installing python libraries

installing some dependent libraries

Note: to use apt-get build-dep, you need to uncomment the deb-src lines in your apt source file (/etc/apt/sources.list) and run apt-get update.

$ sudo apt-get install build-essential gcc-multilib libtool automake autoconf bison debootstrap debian-archive-keyring
$ sudo apt-get build-dep qemu-system
$ sudo apt-get install libacl1-dev

installing pip and setting up virtualenv & wrapper

$ sudo apt-get install python-pip python-virtualenv
$ pip install virtualenvwrapper

Add the following lines to your shell rc file (~/.bashrc or ~/.zshrc).

export WORKON_HOME=$HOME/.virtual_envs
source /usr/local/bin/virtualenvwrapper.sh

Creating a python virtual environment

$ mkvirtualenv tfuzz-env

Installing dependent libraries

This command will install all the dependent python libraries for you.

$ workon tfuzz-env
$ pip install -r req.txt

Fuzzing target programs with T-Fuzz

$ ./TFuzz  --program  <path_to_target_program> --work_dir <work_dir> --target_opts <target_opts>

Where

• <path_to_target_program>: the path to the target program to fuzz
• <work_dir>: the directory to save the results
• <target_opts>: the options to pass to the target program, like AFL, use @@ as placeholder for files to mutate.

Examples

1. Fuzzing base64 with T-Fuzz

$ ./TFuzz  --program  target_programs/base64  --work_dir workdir_base64 --target_opts "-d @@"

2. Fuzzing uniq with T-Fuzz

$ ./TFuzz  --program  target_programs/uniq  --work_dir workdir_uniq --target_opts "@@"

3. Fuzzing md5sum with T-Fuzz

$ ./TFuzz  --program  target_programs/md5sum  --work_dir workdir_md5sum --target_opts "-c @@"

4. Fuzzing who with T-Fuzz

$ ./TFuzz  --program  target_programs/who  --work_dir workdir_who --target_opts "@@"

Using CrashAnalyzer to verify crashes

T-Fuzz CrashAnalyzer has been put in a docker image, however, it is still not working in all binaries we tested, we are still investigating it the cause.

Here is how:

Run the following command to run our docker image

$ [sudo] docker pull tfuzz/tfuzz-test
$ [sudo] docker run  --security-opt seccomp:unconfined -it tfuzz/tfuzz-test  /usr/bin/zsh 

In the container:

There are 3 directories:

• release: contains code the built lava binaries
• results: contains some results we found in lava-m dataset
• radare2: it is a program used by T-Fuzz.

Currently, T-Fuzz may not work, because the tracer crashes accidentally. And the CrashAnalyzer can not work on all results. But some cases can be recovered.

For example:

To verify bugs in base64, first goto release and checkout ca_base64:

$ cd release
$ git checkout ca_base64

Then we use a transformed program to recover the crash in the original program:

1. Choose a transformed program and run it on the input found by a fuzzer:

$ cd ~
$./results/ca_base64/554/base64_tfuzz_28/base64_tfuzz_28 -d ./results/ca_base64/554/crashing_inputs_from/results_saved_0_from 
[1]    131 segmentation fault (core dumped)  ./results/ca_base64/554/base64_tfuzz_28/base64_tfuzz_28 -d

2. Recover an input from this transformed program and crashing input

$ ./release/CrashAnalyzer  --tprogram ./results/ca_base64/554/base64_tfuzz_28/base64_tfuzz_28 --target_opts "-d @@" --crash_input ./results/ca_base64/554/crashing_inputs_from/results_saved_0_from --result_dir base64_result --save_to recover
WARNING | 2018-12-04 04:28:22,350 | angr.analyses.disassembly_utils | Your verison of capstone does not support MIPS instruction groups.
Trying /root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from
WARNING | 2018-12-04 04:28:23,228 | angr.project | Address is already hooked, during hook(0x9021cd0, <SimProcedure ReturnUnconstrained>). Re-hooking.
WARNING | 2018-12-04 04:28:23,228 | angr.project | Address is already hooked, during hook(0x90dd000, <SimProcedure ReturnUnconstrained>). Re-hooking.
WARNING | 2018-12-04 04:28:23,229 | angr.simos.linux | Tracer has been heavily tested only for CGC. If you find it buggy for Linux binaries, we are sorry!
Adding <Bool Or(((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_0_0_8 >= 65) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_0_0_8 <= 90)), ((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_0_0_8 >= 97) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_0_0_8 <= 122)), ((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_0_0_8 >= 48) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_0_0_8 <= 57)), (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_0_0_8 == 43), (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_0_0_8 == 47))>
Adding <Bool Or(((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_1_1_8 >= 65) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_1_1_8 <= 90)), ((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_1_1_8 >= 97) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_1_1_8 <= 122)), ((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_1_1_8 >= 48) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_1_1_8 <= 57)), (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_1_1_8 == 43), (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_1_1_8 == 47))>
Adding <Bool Or(((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_2_2_8 >= 65) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_2_2_8 <= 90)), ((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_2_2_8 >= 97) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_2_2_8 <= 122)), ((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_2_2_8 >= 48) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_2_2_8 <= 57)), (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_2_2_8 == 43), (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_2_2_8 == 47))>
Adding <Bool Or(((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_3_3_8 >= 65) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_3_3_8 <= 90)), ((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_3_3_8 >= 97) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_3_3_8 <= 122)), ((file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_3_3_8 >= 48) && (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_3_3_8 <= 57)), (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_3_3_8 == 43), (file_/root/results/ca_base64/554/crashing_inputs_from/results_saved_0_from_9_3_3_8 == 47))>
results saved to /root/base64_result/recover_0

Then /root/base64_result/recover_0 is generated, we can use it to trigger a crash in the original program.

3. verify the input by running the generated input on the original program

$ ./results/base64 -d base64_result/recover_0 
Successfully triggered bug 554, crashing now!
Successfully triggered bug 554, crashing now!
Successfully triggered bug 554, crashing now!
[1]    177 segmentation fault (core dumped)  ./results/base64 -d base64_result/recover_0