cnspec

Open source, cloud-native security and policy project

cnspec assesses your entire infrastructure's security and compliance. It finds vulnerabilities and misconfigurations across public and private cloud environments, Kubernetes clusters, containers, container registries, servers, endpoints, SaaS products, infrastructure as code, APIs, and more.

A powerful policy as code engine, cnspec is built upon Mondoo's security data fabric. It comes configured with default security policies that run right out of the box. It's both fast and simple to use!

Quick start

bash -c "$(curl -sSL https://install.mondoo.com/sh)"
cnspec scan local

Installation

Install cnspec with our installation script:

Linux and macOS

bash -c "$(curl -sSL https://install.mondoo.com/sh)"

Windows

Set-ExecutionPolicy Unrestricted -Scope Process -Force;
[System.Net.ServicePointManager]::SecurityProtocol = [System.Net.ServicePointManager]::SecurityProtocol -bor 3072;
iex ((New-Object System.Net.WebClient).DownloadString('https://install.mondoo.com/ps1'));
Install-Mondoo;

If you prefer manual installation, you can find the cnspec packages in our releases.

Run a scan with policies

Use the cnspec scan subcommand to check local and remote targets for misconfigurations and vulnerabilities.

Local scan

This command evaluates the security of your local machine:

cnspec scan local

Remote scan targets

You can also specify remote targets to scan. For example:

# to scan a docker image:
cnspec scan docker image ubuntu:22.04

# scan public ECR registry
aws ecr-public get-login-password --region us-east-1 | docker login --username AWS --password-stdin public.ecr.aws/r6z5b8t4
cnspec scan docker image public.ecr.aws/r6z5b8t4

# to scan an AWS account using the local AWS CLI config
cnspec scan aws

# scan an EC2 instance with EC2 Instance Connect
cnspec scan aws ec2 instance-connect root@i-1234567890abcdef0

# to scan a Kubernetes cluster via your local kubectl config or a local manifest file
cnspec scan k8s
cnspec scan k8s manifest.yaml

# to scan a GitHub repository
export GITHUB_TOKEN=<personal_access_token>
cnspec scan github repo <org/repo>

📚 To learn more, read the cnspec docs.

Policies

cnspec policies are built on the concept of policy as code. cnspec comes with default security policies configured for all supported targets. The default policies are available in the content directory of this repository.

Vulnerability scan

cnspec scans for vulnerabilities in a wide range of platforms. Vulnerability scanning is not restricted to container images; it works for build and runtime as well.

NOTE: Vulnerability scanning requires the client to be logged into Mondoo Platform.

Examples

# scan container image
cnspec vuln docker debian:12

# scan aws instance via EC2 instance connect
cnspec vuln aws ec2 instance-connect root@i-1234567890abcdef0

# scan instance via SSH
cnspec vuln ssh user@host

# scan windows via SSH or Winrm
cnspec vuln ssh user@host --ask-pass
cnspec vuln winrm user@host --ask-pass

# scan VMware vSphere ESXi hosts
cnspec vuln vsphere user@host --ask-pass

# scan Linux, Windows
cnspec vuln local

Platform	Versions
Alpine	3.10 - 3.24
AlmaLinux	8, 9, 10
Amazon Linux	1, 2, 2023
Arch Linux	Rolling
CentOS	6, 7, 8, Stream
Debian	8, 9, 10, 11, 12, 13
Fedora	30 - 44
openSUSE	Leap 15, Leap 16
Oracle Linux	6, 7, 8, 9, 10
Photon Linux	2, 3, 4, 5
Red Hat Enterprise Linux	6, 7, 8, 9, 10
Rocky Linux	8, 9, 10
SUSE Linux Enterprise	12, 15, 16
Ubuntu	18.04, 20.04, 22.04, 24.04, 26.04
VMware vSphere ESXi	6, 7, 8, 9
Windows	10, 11, 2016, 2019, 2022, 2025

cnspec interactive shell

cnspec also provides an interactive shell to explore assertions. It helps you understand the assertions that security policies use, as well as write your own policies. It's also a great way to interact with both local and remote targets on the fly.

Local system shell

cnspec shell local

The shell provides a help command for information on the resources that power cnspec. Running help without any arguments lists all of the available resources and their fields. You can also run help <resource> to get more detail on a specific resource. For example:

cnspec> help ports
ports:              TCP/IP ports on the system
  list []port:      List of all TCP/IP ports
  listening []port: All listening ports

The shell uses auto-complete, which makes it easy to explore.

Once inside the shell, you can enter MQL assertions like this:

> ports.listening.none( port == 23 )

To clear the terminal, type clear.

To exit, either hit CTRL + D or type exit.

Prioritize risks that matter with Mondoo Platform

The Mondoo unified security platform finds and prioritizes vulnerabilities and misconfigurations that pose the highest risk to your business. Mondoo's security data fabric analyzes the threat and exposure of every finding within the unique context of your infrastructure. Instead of a flood of irrelevant security alerts, Mondoo shows you how you can make an immediate and significant impact on your security posture.

To get started, contact us.

To learn about Mondoo Platform, read the Mondoo Platform docs or visit mondoo.com.

Register cnspec with Mondoo Platform

To use cnspec with Mondoo Platform, generate a token in the Mondoo App, then run:

cnspec login --token TOKEN

Once authenticated, you can scan any target:

cnspec scan <target>

cnspec returns the results from the scan to STDOUT and to Mondoo Platform.

With an account on Mondoo Platform, you can upload policies:

cnspec bundle upload mypolicy.mql.yaml

Custom policies

A cnspec policy is simply a YAML file that lets you express any security rule or best practice for your fleet.

A few examples can be found in the examples folder in this repo. You can run any of these policies:

cnspec scan local -f examples/example.mql.yaml

If you're interested in writing your own policies or contributing policies back to the cnspec community, read Mondoo's Policy Authoring Guide.