Lab
A Cloud Guru

Configure a Custom Seccomp Profile

In this lab, we need to create a custom seccomp profile which has a default action to allow system calls to occur and bans certain listed system calls. After that, we need to run a test container with our seccomp profile. With that, we will need to conduct some tests to see if the calls on the list were banned or not.

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Path Info

Level

Intermediate

Duration

45m

Published

Apr 03, 2020

Challenge

Check Seccomp Capabilities

grep SECCOMP /boot/config-$(uname -r)

Expected output:

CONFIG_HAVE_ARCH_SECCOMP_FILTER=y
CONFIG_SECCOMP_FILTER=y
CONFIG_SECCOMP=y

Challenge

Create Our Own Policy and Override the Default Seccomp Profile

vim /home/cloud_user/myProfile.json

{
  "defaultAction": "SCMP_ACT_ALLOW",
  "architectures": [
      "SCMP_ARCH_X86_64"
  ],
  "syscalls": [
    {
      "name": "chmod",
      "action": "SCMP_ACT_ERRNO"
    },
    {
      "name": "fchmod",
      "action": "SCMP_ACT_ERRNO"
    },
    {
      "name": "fchmodat",
      "action": "SCMP_ACT_ERRNO"
    },
    {
      "name": "mkdir",
      "action": "SCMP_ACT_ERRNO"
    }
  ]
}

ESC
:wq
ENTER

Challenge

Run a Container with a Custom Seccomp Profile

sudo docker run --rm -it --security-opt seccomp=/home/cloud_user/myProfile.json debian:jessie sh

Challenge

Test the Restrictions within the Container

The following should be denied.

mkdir test

Expected output:

mkdir: cannot create directory 'test': Operation not permitted

The following should work.

touch testFile

The following should be denied.

chmod +x testFile

Expected output:

chmod: changing permissions of 'testFile': Operation not permitted

Author

A Cloud Guru

The Cloud Content team comprises subject matter experts hyper focused on services offered by the leading cloud vendors (AWS, GCP, and Azure), as well as cloud-related technologies such as Linux and DevOps. The team is thrilled to share their knowledge to help you build modern tech solutions from the ground up, secure and optimize your environments, and so much more!

What's a lab?

Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.