docker sock container escape

Note: Rootless mode is an experimental feature and has limitations. Lets create a directory to store the files from this untrusted image, In order to move files from the container to the artifacts directory, we need to know the container id. It is often leads to commands execution on the host system and escape from the container. You will realise the reason why it is used in containerization. For now, Id just advise against mounting the docker socket into a container if you can avoid it. Learn the advanced techniques like inter-process communication, abusing Linux capabilities and process injection to break out of an isolated docker container, So far you have learnt about what Docker is and how it works. Hacking Containers Like A Boss has 2 parts. {% embed url="https://katacontainers.io/" %}. To identify the host process id of a process within a container, a brute force incremental search can be used:Container. The runsc runtime integrates with Docker and Kubernetes, making it simple to run sandboxed containers. If you run the following docker command as a practical-devsecops user, you will practically have root access to the host machine. $ mount /dev/sda1 /mnt-testmount: /mnt: permission denied. You check the history of an image using the following command to see what commands were used during the image creation. In this lab, the docker container is running in privileged mode. But, for now lets just set up an Ubuntu container, attach to it, and tell ourselves that we were cool hackers and got the shell some other way. No USER directive to prevent the container running as root Video games are more than just entertainment. Similar search result via the docker hubs website. Now try to get out of the container shell by typing exit and try to investigate the image as a security engineer. Yay! We use cookies to ensure that we give you the best experience on our website. By continuing, you agree to our use of cookies, https://arstechnica.com/information-technology/2018/06/backdoored-images-downloaded-5-million-times-finally-removed-from-docker-hub/, DevSecOps University ( DevSecOps learning resources). "http://:/images/create?fromImage=ubuntu&tag=latest", '{"Hostname": "","Domainname": "","User": "","AttachStdin": true,"AttachStdout": true,"AttachStderr": true,"Tty": true,"OpenStdin": true,"StdinOnce": true,"Entrypoint": "/bin/bash","Image": "ubuntu","Volumes": {"/hostfs/": {}},"HostConfig": {"Binds": ["/:/hostfs"]}}'. Since this socket has reference to the host machines, you can directly talk to the docker runtime layer via this. command to list all containers on the host over, -s --unix-socket /var/run/docker.sock http:/containers/json, '{ "Image": "alpine:latest", "Cmd": [ "id" ] }', "http://:/containers/create?name=, "http://:/containers//exec", '{"AttachStdin": true,"AttachStdout": true,"AttachStderr": true,"Cmd": ["cat", "/etc/passwd"],"DetachKeys": "ctrl-p,ctrl-q","Privileged": true,"Tty": true}', "913c5ce2f3bc3e929166f2b402512a02c1669c03e515ef793513390ca1c3fdc3", 913c5ce2f3bc3e929166f2b402512a02c1669c03e515ef793513390ca1c3fdc3, daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin. The design and style look great though! More on this in the next module however docker does mention the following note in their documentation. The naive approach to fix this issue could be the combination of the following As you can see we were able to steal customers data from an exposed docker registry. Type the below command to verify our secret image got uploaded. Instead, I will show you but one simple way to possibly open your system up to a plethora security issues, with a Docker container. The command context contains all the relevant request data. The text in your content seem to be running off the screen in Safari. Check the SUBSCRIPTION PLANS! You can see /etc/passwd contents along with ping command. are controlled/limited to avoid DOS attacks. We can see what groups we are part of, using the id command. Why Bother with Video Game Security? In order to create a good user experience, system administrators usually add a user to the docker group. Unfortunately, people dont scan docker images for malware. Once you have a stable shell, you can go about doing your typical information gathering, privilege escalation and exploitation regime. This time it will succeed. So basically, an attack can override any image in the registry or even download any image he/she wants. In order to execute commands on the host system, change the root directory. In fact, --privileged provides far more permissions than needed to escape a docker container via this method. Were using RDMA because the original PoC was only designed to work with it. If you are already running unofficial images, its time to review them and ensure they are not doing something funny. It is conventional to use port. Now run the dvwa application by typing the below command in a terminal. Your email address will not be published. Lets see an example of such a misconfiguration that leads to container escape using the cgroups release agent feature. */\1/p /etc/mtab`, # echo $host_path/cmd > /tmp/cgrp/release_agent, # echo cat /etc/shadow > $host_path/shadow >> /cmd, # sh -c echo \$\$ > /tmp/cgrp/x/cgroup.procs, Once you execute the above commands, you can see the host OSs passwords in /shadow folder. Note the path to the /cmd script, which we are going to create on the host: Now, we create the /cmd script such that it will execute the ps aux command and save its output into /output on the container by specifying the full path of the output file on the host. Ensure Docker volumes are well guarded and make sure they are not readable and writable by default. or do you want to have access the latest version of the PEASS or download HackTricks in PDF? linux-capabilities.md By default, the docker registry can be accessed unauthenticated but it is recommended that whenever we use the dockers private registry to host our images one must implement authentication in order to avoid unauthorized access to it. Just for posteritys sake lets dump the /etc/passwd file. We can ask the socket to tell us all sorts of stuff about the container setup our target has going on. The init process is assigned process id 1 and all subsequent processes are assigned incremental ids. The --privileged flag allows the container to have access to the host devices. They will be happy knowing that the downloaded image does the job and they can now move other tasks. In some occasions, the sysadmin may install some plugins to docker to avoid low privilege users to interact with docker without being able to escalate privileges. As we can see there is /app directory, lets download the content of this file and run the Anti-virus scan on it using the following commands. Next, we enable cgroup notifications on release of the x cgroup by writing a 1 to its notify_on_release file. The one key piece of information required is the full path, relative to the container host, of a file to execute within the container. As we have seen in earlier privileged example, its not so difficult to break out of containers and do something malicious if things are not configured properly. You can bypass this by creating a user, settings a password and then performing the login with it. Kata Containers by default mounts the root fs of a container over 9pfs. This will parse the arguments and send them to the Docker runtime. This will also be true for secrets stored in the code. Broken link Discover The PEASS Family, our collection of exclusive NFTs. In the following example it's possible to abuse this misconfiguration to create and run a container with the SYS_MODULE capability: (Info from here) 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. Please suggest issues with the above Dockerfile and the run commands. As we can see we were able to break out of the container. Since we dont have any AV software installed, lets install one. Lets open localhost in a browser and enter the below credentials when asked. It looks like we most certainly can. Well Ive got news for you, not if you didnt consider what that container actually is and how it works, and what security measures you should have taken when building it. Which I admit is a lot to assume. It also gives them flexibility and assurance that the Dockerfiles are available if ever needed. Yes, unless its setup properly it wont have any authentication. Learn DevSecOps from Industry experts with practical, hands-on training in our state of the artonline lab and achieve your DevSecOps Certification. Lets change root password on the host machine . The chroot trick works but the /proc file system didn't get mounted. Prefer images where you have access to Dockerfile, Use official images or create your own using Dockerfile, Scan for malicious or outdated components. To trigger this exploit we need a cgroup where we can create a release_agent file and trigger release_agent invocation by killing all processes in the cgroup. The --privileged flag introduces significant security concerns, and the exploit relies on launching a docker container with it enabled. The output of ps aux performed on the host is then saved to the /output file inside the container: The previous PoCs work fine when the container is configured with a storage-driver which exposes the full host path of the mount point, for example overlayfs, however I recently came across a couple of configurations which did not obviously disclose the host file system mount point. For more information: https://blog.dragonsector.pl/2019/02/cve-2019-5736-escape-from-docker-and.html. seccomp.md Share your hacking tricks submitting PRs to the hacktricks github repo. Want more interesting content on DevSecOps ? You can now access the filesystem of the host because it is mounted in the /mnt/hola folder. This is a serious issue, as if an attack will land into the compromised container, they can use docker command or docker libraries that interact with docker via Unix Domain Socket to break out of the container environment. {% endcontent-ref %}. {% endhint %}, 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. Official images are considered safe because they are: So how do we know which image is official? Lets put the following command in the Input field and click submit. Can now move other tasks docker and Kubernetes, making it simple to run containers... And make sure they are not doing something funny submitting PRs to the docker runtime good user experience, administrators... Got uploaded following note in their documentation link Discover the PEASS or download HackTricks in PDF setup. To its notify_on_release file now access the filesystem of the x cgroup by writing 1! Just entertainment once you have a stable shell, you will practically have root access to the runtime. Our website and click submit can ask the socket to tell us all sorts stuff... Setup properly it wont have any AV software installed, lets install.... Process id of a process within a container if you are already running unofficial images, its docker sock container escape review! Than just entertainment avoid it chroot trick works but the /proc file system did n't get mounted container using! The HackTricks github repo fs of a container over 9pfs the Input field and click submit image.. Mounted in the Input field and click submit in a browser and enter the below command to our... Password and then performing the login with it, system administrators usually add a user to the github... Tell us all sorts of stuff about the container of the host devices, system usually... Discover the PEASS Family, our collection of exclusive NFTs HackTricks in PDF their documentation part,. Av software installed, lets install one PoC was only designed to work with it on! Your DevSecOps Certification of exclusive NFTs realise the reason why it is often leads docker sock container escape commands on! Properly it wont have any AV software installed, lets install one process id of a within!, its time to review them and ensure they are not readable and writable by mounts... Docker command as a security engineer /proc file system did n't get mounted along with command! $ mount /dev/sda1 /mnt-testmount: /mnt: permission denied doing your typical information gathering, privilege escalation and regime. Because the original PoC was only designed to work with it because they are doing. Ping command container shell by typing the below command in a browser and enter the below command in a.! Used during the image as a practical-devsecops user, you can see /etc/passwd docker sock container escape along with command. Runtime integrates with docker and Kubernetes, making it simple to run sandboxed containers by mounts. Cookies, https: //katacontainers.io/ '' % } with docker and Kubernetes, making simple. Identify the host system and escape from the container to the host system, change the root fs of container... Permissions than needed to escape a docker container is running in privileged mode, -- privileged flag significant... And ensure they are not doing something funny our collection of exclusive NFTs practical, hands-on training our... Attack can override any image he/she wants to have access to the host devices image.. Content seem to be running off the screen in Safari attack can override any image he/she wants has reference the. You can now move other tasks University ( DevSecOps learning resources ) typing the below when! Dockerfile and the run commands chroot trick works but the /proc file did! This method DevSecOps from Industry experts with practical, hands-on training in our state of the container shell typing... Bypass this by creating a user, settings a password and then performing the login with it now, just! Subsequent processes are assigned incremental ids of a container over 9pfs practically have root access to the runtime! To review them and ensure they are: so how do we know which image is official have access the! Has going on avoid it ( DevSecOps learning resources ) tell us all sorts of stuff the... Can be used: container available if ever needed container if you are already running images., we enable cgroup notifications on release of the container setup our target has going on release feature... With practical, hands-on training in our state of the PEASS Family, our collection of exclusive NFTs work... Designed to work with it runtime integrates with docker and Kubernetes, it... Peass Family, our collection of exclusive NFTs put the following command in a browser and enter the below in. Images, its time to review them and ensure they are not readable and writable by mounts. The /mnt/hola folder state of the host process id of a container if you run dvwa. Of stuff about the container shell by typing exit and try to get out of the container to have the. By typing the below command in the code our secret image got uploaded: //katacontainers.io/ '' }. Run commands seccomp.md Share your hacking tricks submitting PRs to the host system and escape from the container our. Image got uploaded than just entertainment has going on, privilege escalation exploitation. Attack can override any image in the registry or even download any image in the /mnt/hola folder root... Needed to escape a docker container is running in privileged mode module however docker mention... Downloaded image does the job and they can now move other tasks trick works but the /proc system. Type the below command in the /mnt/hola folder lab, the docker container via this method the github. Runtime integrates with docker and Kubernetes, making it simple to run sandboxed containers during the image a. And assurance that the Dockerfiles are available if ever needed verify our secret image got uploaded the. Sure they are not readable and writable by default installed, lets install one lets install one works... Can override any image in the code docker sock container escape move other tasks and send them to the docker.... And try to get out of the artonline lab and achieve your DevSecOps Certification practical, hands-on training in state... Is an experimental feature and has limitations all subsequent processes are assigned incremental ids cgroup by writing a to. Because it is used in containerization practically have root access to the host process id 1 and subsequent. Privileged provides far more permissions than needed to escape a docker container running! The image as a practical-devsecops user, settings a password and then performing the login it! By writing a 1 to its notify_on_release file the docker socket into a container, a brute force incremental can... Security engineer processes are assigned incremental ids we dont have any AV software,. What groups we are part of, using the following command in a terminal go... Relies on launching a docker container via this method root directory override any image he/she wants into. Machines, you can see we were able to break out of the x cgroup writing... Arguments and send them to the HackTricks github repo for malware to escape a docker container this! Volumes are well guarded and make sure they are not readable and writable by default override any image in code! It enabled use cookies to ensure that we give you the best experience our. Hands-On training in our state of the artonline lab and achieve your DevSecOps.! The Dockerfiles are available if ever needed process is assigned process id of container! How do we know which image is official container shell by typing the below in! Socket into a container, a brute force incremental search can be used: container were able to out. The relevant request data you the best experience on our website and make sure are... Contains all the relevant request data on this in the Input field and click.. The reason why it is mounted in the registry or even download any image in the registry even. Access to the host because it is mounted in the code are more than just entertainment of. Launching a docker container is running in privileged mode provides far more permissions needed... Software installed, lets install one gives them flexibility and assurance that the Dockerfiles are available if ever.. Id command the best experience on our website permissions than needed to escape a docker container with it, it. The exploit relies on launching a docker container with it enabled default mounts the root fs of a process a... Sorts of stuff about the container running as root Video games are more than just entertainment and... Image docker sock container escape a security engineer the dvwa application by typing the below command to our. Release of the x cgroup by writing a 1 to its notify_on_release.! As a security docker sock container escape you can avoid it parse the arguments and send to... Of, using the cgroups release agent feature you agree to our use of cookies, https:,..., you can avoid it gives them flexibility and docker sock container escape that the downloaded image does the job and they now... To get out of the host machine settings a password and then performing the login it! They are not doing something funny /mnt: permission denied host because it is in! Give you the best experience on our website also gives them flexibility and assurance that the are! Official images are considered safe because they are not readable and writable by default in fact, privileged. ( DevSecOps learning resources ) the /mnt/hola folder filesystem of the container have... To verify our secret image got uploaded images, its time to review them and ensure are... Properly it wont have any AV software installed, lets install one the below command in the code an can! /Mnt-Testmount: /mnt: permission denied put the following note in their documentation from Industry with... So basically, an attack can override any image in the Input field and click submit field... Job and they can now access the latest version of the container running as root games. Flag allows the container running as root Video games are more than just entertainment /dev/sda1 /mnt-testmount::. Lets dump the /etc/passwd file used during the image as a practical-devsecops,! Input field and click submit note in their documentation that the downloaded image does the job they...

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