kube-bench

The Kubernetes Bench for Security is a Go application that checks whether Kubernetes is deployed securely by running the checks documented in the CIS Kubernetes 1.6 Benchmark v1.0.0.

Tests are configured with YAML files, making this tool easy to update as test specifications evolve.

Installation

You can either install kube-bench through a dedicated container, or compile it from source:

1. Container installation: Run docker run --rm -v `pwd`:/host aquasec/kube-bench:latest. This will copy the kube-bench binary and configuration to you host. You can then run ./kube-bench <master|node>.

2. Install from sources: If Go is installed on the target machines, you can simply clone this repository and run as follows: go get github.com/aquasecurity/kube-bench cp $GOROOT/bin/kube-bench . ./kube-bench <master|node>

Usage

./kube-bench [command]

Available Commands:
  master      Checks for Kubernetes master node
  node        Checks for Kubernetes node
  federated   Checks for Kubernetes federated deployment
  help        Help information

Flags:
  -c, --check string   A comma-delimited list of checks to run as specified in CIS document. Example --check="1.1.1,1.1.2"
  -g, --group string   Run all the checks under this comma-delimited list of groups. Example --group="1.1"
  -h, --help           help for kube-bench
  --json               Output results as JSON

Test config YAML representation

The tests are represented as YAML documents (installed by default into ./cfg).

An example is as listed below:

---
controls:
id: 1
text: "Master Checks"
type: "master"
groups:
- id: 1.1
  text: "Kube-apiserver"
  checks:
    - id: 1.1.1
      text: "Ensure that the --allow-privileged argument is set (Scored)"
      audit: "ps -ef | grep kube-apiserver | grep -v grep"
      tests:
      bin_op: or
      test_items:
      - flag: "--allow-privileged"
        set: true
      - flag: "--some-other-flag"
        set: false
      remediation: "Edit the /etc/kubernetes/config file on the master node and set the KUBE_ALLOW_PRIV parameter to '--allow-privileged=false'"
      scored: true

Recommendations (called checks in this document) can run on Kubernetes Master, Node or Federated API Servers. Checks are organized into groups which share similar controls (things to check for) and are grouped together in the section of the CIS Kubernetes document. These groups are further organized under controls which can be of the type master, node or federated apiserver to reflect the various Kubernetes node types.

Tests

Tests are the items we actually look for to determine if a check is successful or not. Checks can have multiple tests, which must all be successful for the check to pass.

The syntax for tests:

tests:
- flag:
  set:
  compare:
    op:
    value:
...

Tests have various operations which are used to compare the output of audit commands for success. These operations are:

• eq: tests if the flag value is equal to the compared value.
• noteq: tests if the flag value is unequal to the compared value.
• gt: tests if the flag value is greater than the compared value.
• gte: tests if the flag value is greater than or equal to the compared value.
• lt: tests if the flag value is less than the compared value.
• lte: tests if the flag value is less than or equal to the compared value.
• has: tests if the flag value contains the compared value.
• nothave: tests if the flag value does not contain the compared value.