Blazing fast x86-64 VM kernel fuzzing framework with performant VM reloads for Linux, MacOS and Windows.
Published at USENIX Security 2017.
- full documentation
- agents for macOS and Windows (except for our test driver)
@inproceedings{schumilo2017kafl,
author = {Schumilo, Sergej and Aschermann, Cornelius and Gawlik, Robert and Schinzel, Sebastian and Holz, Thorsten},
title = {{kAFL: Hardware-Assisted Feedback Fuzzing for OS Kernels}},
year = {2017},
booktitle = {USENIX Security Symposium}
}
- Linux keyctl null pointer dereference (CVE-2016-8650)
- Linux EXT4 memory corruption
- Linux EXT4 denial of service
- macOS APFS memory corruption (CVE-2017-13800)
- macOS HFS memory corruption (CVE-2017-13830)
This is a short introduction on how to setup kAFL to fuzz Linux kernel components.
$ git clone https://github.com/RUB-SysSec/kAFL.git
$ cd kAFL
$ chmod u+x install.sh
$ sudo ./install.sh
$ sudo reboot
- Create QEMU hard drive image:
$ qemu-img create -f qcow2 linux.qcow2 20G
- Retrieve an ISO file of the desired OS and install it inside a VM (in this case Ubuntu 16.04 server):
$ wget -O /path/to/where/to/store/ubuntu.iso http://de.releases.ubuntu.com/16.04/ubuntu-16.04.3-server-amd64.iso
$ qemu-system-x86_64 -cpu host -enable-kvm -m 512 -hda linux.qcow2 -cdrom ubuntu.iso -usbdevice tablet
- Download kAFL and compile the loader agent:
git clone https://github.com/RUB-SysSec/kAFL.git
cd path/to/kAFL/kAFL-Fuzzer/agents
chmod u+x compile.sh
./compile.sh
- Shutdown the VM
- On the host: Create Overlay and Snapshot Files:
mkdir snapshot && cd snapshot
qemu-img create -b /absolute/path/to/hdd/linux.qcow2 -f qcow2 overlay_0.qcow2
qemu-img create -f qcow2 ram.qcow2 512
- Start the VM using QEMU-PT:
cd /path/to/kAFL
./qemu-2.9.0/x86_64-softmmu/qemu-system-x86_64 -hdb /path/to/snapshot/ram.qcow2 -hda /path/to/snapshot/overlay_0.qcow2 -machine pc-i440fx-2.6 -serial mon:stdio -enable-kvm -k de -m 512
- (Optional) Install and load the vulnerable Test Driver:
cd path/to/kAFl/kAFL-Fuzzer/vuln_drivers/simple/linux_x86-64/
chmod u+x load.sh
sudo ./load.sh
- Execute loader binary which is in
path/to/kAFL/kAFL-Fuzzer/agents/linux_x86_64/loader/asroot. VM should freeze. Switch to the QEMU management console and create a snapshot:
# press CTRL-a + c
savevm kafl
q
-
Edit
/path/to/kAFL/kAFL-Fuzzer/kafl.ini(qemu-kafl_locationto point topath/to/kAFL/qemu-2.9.0/x86_64-softmmu/qemu-system-x86_64) -
Compile agents:
cd <KERNEL_AFL_ROOT>/kAFL-Fuzzer/agents
chmod u+x compile.sh
./compile.sh
- Retrieve address ranges of loaded drivers:
cd /path/to/kAFL/kAFL-Fuzzer
python kafl_info.py /path/to/snapshot/ram.qcow2 /path/to/snapshot/ agents/linux_x86_64/info/info 512 -v
python kafl_fuzz.py /path/to/snapshot/ram.qcow2 /path/to/snapshot agents/linux_x86_64/fuzzer/kafl_vuln_test 512 /path/to/input/directory /path/to/working/directory -ip0 0xffffffffc0287000-0xffffffffc028b000 -v --Purge
The value ip0 is the address range of the fuzzing target.
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