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* [**linpeas**](https://github.com/carlospolop/PEASS-ng/tree/master/linPEAS): It can also **enumerate containers**
* [**CDK**](https://github.com/cdk-team/CDK#installationdelivery): This tool is pretty **useful to enumerate the container you are into even try to escape automatically**
* [**amicontained**](https://github.com/genuinetools/amicontained): Useful tool to get the privileges the container has in order to find ways to escape from it
* [**deepce**](https://github.com/stealthcopter/deepce): Tool to enumerate and escape from containers
* [**grype**](https://github.com/anchore/grype): Get the CVEs contained in the software installed in the image
In case the **docker socket is in an unexpected place** you can still communicate with it using the **`docker`** command with the parameter **`-H unix:///path/to/docker.sock`**
Docker daemon might be also [listening in a port (by default 2375, 2376)](../../../../network-services-pentesting/2375-pentesting-docker.md) or on Systemd-based systems, communication with the Docker daemon can occur over the Systemd socket `fd://`.
You should check the capabilities of the container, if it has any of the following ones, you might be able to scape from it: **`CAP_SYS_ADMIN`**_,_ **`CAP_SYS_PTRACE`**, **`CAP_SYS_MODULE`**, **`DAC_READ_SEARCH`**, **`DAC_OVERRIDE, CAP_SYS_RAWIO`, `CAP_SYSLOG`, `CAP_NET_RAW`, `CAP_NET_ADMIN`**
The `--privileged` flag significantly lowers container security, offering **unrestricted device access** and bypassing **several protections**. For a detailed breakdown, refer to the documentation on `--privileged`'s full impacts.
With these permissions you can just **move to the namespace of a process running in the host as root** like init (pid:1) just running: `nsenter --target 1 --mount --uts --ipc --net --pid -- bash`
Test it in a container executing:
```bash
docker run --rm -it --pid=host --privileged ubuntu bash
Well configured docker containers won't allow command like **fdisk -l**. However on miss-configured docker command where the flag `--privileged` or `--device=/dev/sda1` with caps is specified, it is possible to get the privileges to see the host drive.
Within the container, an attacker may attempt to gain further access to the underlying host OS via a writable hostPath volume created by the cluster. Below is some common things you can check within the container to see if you leverage this attacker vector:
In the previous exploits the **absolute path of the container inside the hosts filesystem is disclosed**. However, this isn’t always the case. In cases where you **don’t know the absolute path of the container inside the host** you can use this technique:
There are several files that might mounted that give **information about the underlaying host**. Some of them may even indicate **something to be executed by the host when something happens** (which will allow a attacker to escape from the container).\
In several occasions you will find that the **container has some volume mounted from the host**. If this volume wasn’t correctly configured you might be able to **access/modify sensitive data**: Read secrets, change ssh authorized\_keys…
### Privilege Escalation with 2 shells and host mount
If you have access as **root inside a container** that has some folder from the host mounted and you have **escaped as a non privileged user to the host** and have read access over the mounted folder.\
You can create a **bash suid file** in the **mounted folder** inside the **container** and **execute it from the host** to privesc.
```bash
cp /bin/bash . #From non priv inside mounted folder
# You need to copy it from the host as the bash binaries might be diferent in the host and in the container
chown root:root bash #From container as root inside mounted folder
chmod 4777 bash #From container as root inside mounted folder
If you have access as **root inside a container** and you have **escaped as a non privileged user to the host**, you can abuse both shells to **privesc inside the host** if you have the capability MKNOD inside the container (it's by default) as [**explained in this post**](https://labs.withsecure.com/blog/abusing-the-access-to-mount-namespaces-through-procpidroot/).\
With such capability the root user within the container is allowed to **create block device files**. Device files are special files that are used to **access underlying hardware & kernel modules**. For example, the /dev/sda block device file gives access to **read the raw data on the systems disk**.
Docker safeguards against block device misuse within containers by enforcing a cgroup policy that **blocks block device read/write operations**. Nevertheless, if a block device is **created inside the container**, it becomes accessible from outside the container via the **/proc/PID/root/** directory. This access requires the **process owner to be the same** both inside and outside the container.
# get the real PID of the shell inside the container as the new https://app.gitbook.com/s/-L_2uGJGU7AVNRcqRvEi/~/changes/3847/linux-hardening/privilege-escalation/docker-breakout/docker-breakout-privilege-escalation#privilege-escalation-with-2-shells user
If you somehow have privileged **access over a process outside of the container**, you could run something like `nsenter --target <pid> --all` or `nsenter --target <pid> --mount --net --pid --cgroup` to **run a shell with the same ns restrictions** (hopefully none) **as that process.**
If a container was configured with the Docker [host networking driver (`--network=host`)](https://docs.docker.com/network/host/), that container's network stack is not isolated from the Docker host (the container shares the host's networking namespace), and the container does not get its own IP-address allocated. In other words, the **container binds all services directly to the host's IP**. Furthermore the container can **intercept ALL network traffic that the host** is sending and receiving on shared interface `tcpdump -i eth0`.
For instance, you can use this to **sniff and even spoof traffic** between host and metadata instance.
* [Writeup: How to contact Google SRE: Dropping a shell in cloud SQL](https://offensi.com/2020/08/18/how-to-contact-google-sre-dropping-a-shell-in-cloud-sql/)
You will be able also to access **network services binded to localhost** inside the host or even access the **metadata permissions of the node** (which might be different those a container can access).
With `hostIPC=true`, you gain access to the host's inter-process communication (IPC) resources, such as **shared memory** in `/dev/shm`. This allows reading/writing where the same IPC resources are used by other host or pod processes. Use `ipcs` to inspect these IPC mechanisms further.
The second technique explained in the post [https://labs.withsecure.com/blog/abusing-the-access-to-mount-namespaces-through-procpidroot/](https://labs.withsecure.com/blog/abusing-the-access-to-mount-namespaces-through-procpidroot/) indicates how you can abuse bind mounts with user namespaces, to affect files inside the host (in that specific case, delete files).
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In case you can execute `docker exec` as root (probably with sudo), you try to escalate privileges escaping from a container abusing CVE-2019-5736 (exploit [here](https://github.com/Frichetten/CVE-2019-5736-PoC/blob/master/main.go)). This technique will basically **overwrite** the _**/bin/sh**_ binary of the **host****from a container**, so anyone executing docker exec may trigger the payload.
Change the payload accordingly and build the main.go with `go build main.go`. The resulting binary should be placed in the docker container for execution.\
Upon execution, as soon as it displays `[+] Overwritten /bin/sh successfully` you need to execute the following from the host machine:
`docker exec -it <container-name> /bin/sh`
This will trigger the payload which is present in the main.go file.
For more information: [https://blog.dragonsector.pl/2019/02/cve-2019-5736-escape-from-docker-and.html](https://blog.dragonsector.pl/2019/02/cve-2019-5736-escape-from-docker-and.html)
There are other CVEs the container can be vulnerable too, you can find a list in [https://0xn3va.gitbook.io/cheat-sheets/container/escaping/cve-list](https://0xn3va.gitbook.io/cheat-sheets/container/escaping/cve-list)
* **Namespaces:** The process should be **completely separated from other processes** via namespaces, so we cannot escape interacting with other procs due to namespaces (by default cannot communicate via IPCs, unix sockets, network svcs, D-Bus, `/proc` of other procs).
* **Root user**: By default the user running the process is the root user (however its privileges are limited).
* **Capabilities**: Docker leaves the following capabilities: `cap_chown,cap_dac_override,cap_fowner,cap_fsetid,cap_kill,cap_setgid,cap_setuid,cap_setpcap,cap_net_bind_service,cap_net_raw,cap_sys_chroot,cap_mknod,cap_audit_write,cap_setfcap=ep`
* **Syscalls**: These are the syscalls that the **root user won't be able to call** (because of lacking capabilities + Seccomp). The other syscalls could be used to try to escape.
If you are in **userspace** (**no kernel exploit** involved) the way to find new escapes mainly involve the following actions (these templates usually require a container in privileged mode):
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<summary><strong>Learn AWS hacking from zero to hero with</strong><ahref="https://training.hacktricks.xyz/courses/arte"><strong>htARTE (HackTricks AWS Red Team Expert)</strong></a><strong>!</strong></summary>
* If you want to see your **company advertised in HackTricks** or **download HackTricks in PDF** Check the [**SUBSCRIPTION PLANS**](https://github.com/sponsors/carlospolop)!
* Discover [**The PEASS Family**](https://opensea.io/collection/the-peass-family), our collection of exclusive [**NFTs**](https://opensea.io/collection/the-peass-family)
* **Join the** 💬 [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** 🐦 [**@carlospolopm**](https://twitter.com/carlospolopm)**.**
* **Share your hacking tricks by submitting PRs to the** [**HackTricks**](https://github.com/carlospolop/hacktricks) and [**HackTricks Cloud**](https://github.com/carlospolop/hacktricks-cloud) github repos.