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Testing Docker Images Security All Day DevOps 2017

jmortegac
October 24, 2017

Testing Docker Images Security All Day DevOps 2017

Testing Docker Images Security All Day DevOps 2017

jmortegac

October 24, 2017
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  2. jmortega.github.io about.me/jmortegac Software Engineer & Security Researcher

  3. Introduction to docker security Security best practices Tools for auditing

    docker images Three Takeaways
  4. • “Docker containers wrap up a piece of software in

    a complete filesystem that contains everything it needs to run: code,runtime, system tools, system libraries –anything you can install on a server. This guarantees that it will always run the same,regardless of the environment it is running in.”
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  6. • Docker provides an additional layer of isolation, making your

    infrastructure safer by default. • Makes the application lifecycle fast and easier, reducing risks in your applications
  7. • Docker uses several mechanisms for security: ◦ Linux kernel

    namespaces ◦ Linux Control Groups (cgroups) ◦ The Docker daemon ◦ Linux capabilities (libcap) ◦ Linux security mechanisms like AppArmor or SELinux
  8. • Namespaces:provides an isolated view of the system where processes

    cannot see other processes in other containers • Each container also gets its own network stack. • A container doesn’t get privileged access to the sockets or interfaces of another container.
  9. • Cgroups: kernel feature that limits and isolates the resource

    usage(CPU,memory,network) of a collection of processes. • Linux Capabilities: divides the privileges of root into distinct units and smaller groups of privileges.
  10. • The docker daemon (/usr/bin/docker) is responsible for managing the

    control groups, orchestrating the namespaces, and so on so that docker images can be run and secured. • Because of the need to manage kernel functions, Docker runs with root privileges. • Limit the users who have control of the Docker Daemon
  11. • Restrict access to the daemon only to the ones

    really needing it (users, processes) • Don’t expose the daemon to the outside your network • If you do so, make sure you have put this behind a secure proxy, like NGINX
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  16. https://github.com/CenturyLinkLabs/dockerfile-from-image

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  18. • Images are extracted in a chrooted sub process, being

    the first-step in a wider effort toward privilege separation. • From Docker 1.10, all images are stored and accessed by the cryptographic checksums of their contents, limiting the possibility of an attacker causing a collision with an existing image Docker Content Trust.
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  20. • Protects against untrusted images • Can enable signing checks

    on every managed host • Signature verification transparent to users • Guarantee integrity of your images when pulled • Provides trust from publisher to consumer • export DOCKER_CONTENT_TRUST=1 • ~/.docker/trust/trusted-certificates/
  21. • Do not write secrets(users and passwords). • Remove unnecessary

    setuid, setgid permissions (Privilege escalation) • Download packages securely using GPG and certificates • Try to restrict an image or container to one service
  22. • To disable setuid rights, add the following to the

    Dockerfile of your image
  23. • Set a specific user. • Don’t run your applications

    as root in containers.
  24. • Don’t run containers with --privileged flag • The --privileged

    flag gives all capabilities to the container. • docker run --privileged … • docker run --cap-drop=ALL --cap-add= CAP_NET_ADMIN ...
  25. • Manual management within the container: docker run --cap-add ALL

    • Restricted capabilities with root: docker run --cap-drop ALL --cap-add $CAP • No capabilities: docker run --user
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  28. • We can verify the integrity of the image •

    Checksum validation when pulling image from docker hub • Pulling by digest to enforce consistent
  29. • Pulling by Docker content trust • $ export DOCKER_CONTENT_TRUST=1

    $ docker pull debian:latest Pull (1 of 1): debian:[email protected]:a25306f38…
  30. • Check packages installed in the container

  31. Docker security is about limiting and controlling the attack surface

    on the kernel.
  32. Run filesystems as read-only so that attackers can not overwrite

    data or save malicious scripts to the image.
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  36. Auditing Docker Images

  37. • You can scan your images for known vulnerabilities •

    There are tools for that, like Docker Security Scanning, Docker Bench Security and CoreOS Clair • Find known vulnerable binaries
  38. • Checks based on best practices for hosts and containers

    • Find Common Vulnerabilities and Exposures (CVEs) https://docs.docker.com/docker-cloud/builds/image-scan/
  39. • Checks against CVE database for image layers • Binary

    scanning of all components in the image • Performs binary scan to pick up on statically linked binaries • Analyses libraries statically compiled in the image • Generates a reports that shows if there are CVE in the libraries inside the image
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  42. https://www.docker.com/docker-cve-database

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  45. • Vulnerability Static Analysis for Containers • https://github.com/coreos/clair

  46. • You've found an image by searching the internet and

    want to determine if it's safe enough for you to use in production. • You're regularly deploying into a containerized production environment and want operations to alert or block deployments on insecure software.
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  49. • Checks based on best practices for hosts and containers

    • https://github.com/docker/docker-bench-security • Open-source tool for running automated tests • Inspired by the CIS Docker 1.11 benchmark • Runs against containers currently running on same host • Checks for AppArmor, read-only volumes, etc...
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  51. • The host configuration • The Docker daemon configuration •

    The Docker daemon configuration files • Container images and build files • Container runtime • Docker security operations
  52. • The Docker daemon configuration • [WARN] 2.1- Restrict network

    traffic between containers • [WARN] 4.1 - Create a user for the container • [WARN] * Running as root: • [WARN] 5.4 - Restrict Linux Kernel Capabilities within containers • [WARN] * Capabilities added: CapAdd=[audit_control] • [WARN] 5.13 - Mount container's root filesystem as readonly • [WARN] * Container running with root FS mounted R/W:
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  54. • Lynis • Dagda • Anchore

  55. • https://github.com/CISOfy/lynis-docker • Lynis is a Linux, Mac and Unix

    security auditing and system hardening tool that includes a module to audit Dockerfiles. • lynis audit dockerfile <file>
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  57. • https://github.com/eliasgranderubio/dagda • Static analysis of known vulnerabilities on Docker

    containers • Allows monitoring Docker containers for detecting anomalous activities
  58. Python 3 MongoDB PyMongo Requests Python-dateutil Joblib Docker-py Flask Flask-cors

    PyYAML
  59. • python3 dagda.py check --docker_image <image_name> • python3 dagda.py history

    <image_name> --id <Id_Scan>
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  71. Signing • Secure & sign your source Dependences • Pin

    & verify your dependencies Content Trust • Sign your artifacts with Docker Content Trust Privileges • Least Privilege configurations
  72. • https://docs.docker.com/engine/security • http://www.oreilly.com/webops-perf/free/files/dock er-security.pdf • http://container-solutions.com/content/uploads/201 5/06/15.06.15_DockerCheatSheet_A2.pdf • https://www.openshift.com/promotions/docker-sec

    urity.html
  73. • Docker Content Trust https://docs.docker.com/engine/security/trust/cont ent_trust • Docker Security Scanning

    https://docs.docker.com/docker-cloud/builds/image-scan https://blog.docker.com/2016/04/docker-security http://softwaretester.info/docker-audit
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  76. jmortega.github.io @jmortegac Thanks!

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  79. bit.ly/addo-slack Find me on slack, right now!