Kubesec

🚨 v1 API is deprecated, please read the release notes 🚨

Security risk analysis for Kubernetes resources

Live demo

Visit Kubesec.io

This uses ControlPlane's hosted API at v2.kubesec.io/scan

---

• Download Kubesec
  • Command line usage
  • Usage example
  • Docker usage
• Kubesec HTTP Server
  • CLI usage example
  • Docker usage example
• Kubesec-as-a-Service
  • Command line usage
  • Usage example
• Example output
• Contributors
• Getting Help
• Contributing
• Changelog

Download Kubesec

Kubesec is available as a:

• Docker container image at docker.io/kubesec/kubesec:v2
• Linux/MacOS/Win binary (get the latest release)
• Kubernetes Admission Controller
• Kubectl plugin

Or install the latest commit from GitHub with:

Go 1.16+

$ go install github.com/controlplaneio/kubesec/v2@latest

Go version < 1.16

$ GO111MODULE="on" go get github.com/controlplaneio/kubesec/v2

Command line usage:

$ kubesec scan k8s-deployment.yaml

Usage example:

$ cat <<EOF > kubesec-test.yaml
apiVersion: v1
kind: Pod
metadata:
  name: kubesec-demo
spec:
  containers:
  - name: kubesec-demo
    image: gcr.io/google-samples/node-hello:1.0
    securityContext:
      readOnlyRootFilesystem: true
EOF
$ kubesec scan kubesec-test.yaml

Docker usage:

Run the same command in Docker:

$ docker run -i kubesec/kubesec:v2 scan /dev/stdin < kubesec-test.yaml

Specify custom schema

Kubesec leverages kubeconform (thanks @yannh) to validate the manifests to scan. This implies that specifying different schema locations follows the rules as described in the kubeconform README.

Here is a quick overview on how this work for scanning a pod manifest:

• I want to use the latest available schema from upstream.

kubesec [scan|http]

Schema will be fetched from: https://raw.githubusercontent.com/yannh/kubernetes-json-schema/master/master-standalone-strict/pod-v1.json

• I want to use a specific schema version from upstream. (Formatted x.y.z with no v prefix)

kubesec [scan|http] --kubernetes-version <version>

Schema will be fetched from: https://raw.githubusercontent.com/yannh/kubernetes-json-schema/master/v1.25.3-standalone-strict/pod-v1.json

• I want to use a specific schema version in an airgap environment over HTTP.

kubesec [scan|http] --kubernetes-version <version> --schema-location https://host.server

Schema will be fetched from: https://host.server/v<version>-standalone-strict/pod-v1.json

• I want to use a specific schema version in an airgap environment with local files:

kubesec [scan|http] --kubernetes-version <version> --schema-location /opt/schemas

Schema will be read from: /opt/schemas/v<version>-standalone-strict/pod-v1.json

Note: in order to limit external network calls and allow usage in airgap environments, the kubesec image embeds schemas. If you are looking to change the schema location, you'll need to change the K8S_SCHEMA_VER and SCHEMA_LOCATION environment variables at runtime.

Print the scanning rules with their associated scores

All the scanning rules can be printed in in different formats (json (default), yaml and table). This is useful to easily get the point associated with each rule:

kubesec print-rules

which produces the following output:

[
  {
    "id": "AllowPrivilegeEscalation",
    "selector": "containers[] .securityContext .allowPrivilegeEscalation == true",
    "reason": "Ensure a non-root process can not gain more privileges",
    "kinds": [
      "Pod",
      "Deployment",
      "StatefulSet",
      "DaemonSet"
    ],
    "points": -7,
    "advise": 0
  },
...
]

Kubesec HTTP Server

Kubesec includes a bundled HTTP server

The listen address for the HTTP server can be configured by setting KUBESEC_ADDR environment variable. The value can be a single port such as 8080 or an address in the form of ip:port or [ipv6]:port.

CLI usage example:

Start the HTTP server in the background

$ kubesec http 8080 &
[1] 12345
{"severity":"info","timestamp":"2019-05-12T11:58:34.662+0100","caller":"server/server.go:69","message":"Starting HTTP server on port 8080"}

Use curl to POST a file to the server

$ curl -sSX POST --data-binary @test/asset/score-0-cap-sys-admin.yml http://localhost:8080/scan
[
  {
    "object": "Pod/security-context-demo.default",
    "valid": true,
    "message": "Failed with a score of -30 points",
    "score": -30,
    "scoring": {
      "critical": [
        {
          "selector": "containers[] .securityContext .capabilities .add == SYS_ADMIN",
          "reason": "CAP_SYS_ADMIN is the most privileged capability and should always be avoided",
          "points": -30
        },
        {
          "selector": "containers[] .securityContext .runAsNonRoot == true",
          "reason": "Force the running image to run as a non-root user to ensure least privilege",
          "points": 1
        },
  // ...

Finally, stop the Kubesec server by killing the background process

$ kill %

Docker usage example:

Start the HTTP server using Docker

$ docker run -d -p 8080:8080 kubesec/kubesec:v2 http 8080

Use curl to POST a file to the server

$ curl -sSX POST --data-binary @test/asset/score-0-cap-sys-admin.yml http://localhost:8080/scan
...

Don't forget to stop the server.

Kubesec-as-a-Service

Kubesec is also available via HTTPS at v2.kubesec.io/scan

Please do not submit sensitive YAML to this service.

The service is ran on a good faith best effort basis.

Command line usage:

$ curl -sSX POST --data-binary @"k8s-deployment.yaml" https://v2.kubesec.io/scan

Usage example:

Define a BASH function

$ kubesec ()
{
    local FILE="${1:-}";
    [[ ! -e "${FILE}" ]] && {
        echo "kubesec: ${FILE}: No such file" >&2;
        return 1
    };
    curl --silent \
      --compressed \
      --connect-timeout 5 \
      -sSX POST \
      --data-binary=@"${FILE}" \
      https://v2.kubesec.io/scan
}

POST a Kubernetes resource to v2.kubesec.io/scan

$ kubesec ./deployment.yml

Return non-zero status code is the score is not greater than 10

$ kubesec ./score-9-deployment.yml | jq --exit-status '.score > 10' >/dev/null
# status code 1

Example output

Kubesec returns a JSON array, and can scan multiple YAML documents in a single input file.

[
  {
    "object": "Pod/security-context-demo.default",
    "valid": true,
    "message": "Failed with a score of -30 points",
    "score": -30,
    "scoring": {
      "critical": [
        {
          "selector": "containers[] .securityContext .capabilities .add == SYS_ADMIN",
          "reason": "CAP_SYS_ADMIN is the most privileged capability and should always be avoided",
          "points": -30
        }
      ],
      "advise": [
        {
          "selector": "containers[] .securityContext .runAsNonRoot == true",
          "reason": "Force the running image to run as a non-root user to ensure least privilege",
          "points": 1
        },
        {
          // ...
        }
      ]
    }
  }
]

Note

You can also cat multiple files, as long as they're correctly formatted as multiple documents separated by ---. E.g.

{ cat test/asset/multi.yml;
echo "---";
cat test/asset/critical-double-multiple.yml;
} | dist/kubesec scan -

---

Contributing

Check out CONTRIBUTING.md for more information.

Getting Help

If you have any questions about Kubesec and Kubernetes security:

• Read the Kubesec docs
• Reach out on Twitter to @sublimino or @controlplaneio
• File an issue

Your feedback is always welcome!