github.com/jeniawhite/csp-security-policies

Cloud Security Posture - Rego policies

.
├── compliance                         # Compliance policies
│   ├── lib
│   │   ├── common.rego                # Common functions
│   │   ├── common_tests.rego          # Common functions tests
│   │   ├── data_adapter.rego          # Input data adapter
│   │   └── test.rego                  # Common Test functions
│   ├── cis_k8s
│   │   ├── cis_k8s.rego               # Handles all Kubernetes CIS rules evalutations
│   │   ├── test_data.rego             # CIS Test data generators
│   │   ├── schemas                    # Benchmark's schemas
│   │   │   └── input_scehma.rego
│   │   ├── rules
│   │   │   ├── cis_1_1_1              # CIS 1.1.1 rule package
│   │   │   │   ├── rule.rego
│   │   │   │   └── test.rego
│   │   │   │   └── data.yaml          # Rule's metadata
│   │   │   └── ...
└── main.rego                          # Evaluates all policies and returns the findings

Local Evaluation

Add the following configuration files into the root folder

data.yaml

should contain the list of rules you want to evaluate (also supports json)

activated_rules:
  cis_k8s:
    - cis_1_1_1
    - cis_1_1_2
  cis_eks:
    - cis_3_1_1
    - cis_3_1_2

input.json

should contain an beat/agent output, e.g. filesystem data

{
  "type": "file",
  "resource": {
    "mode": "0700",
    "path": "/hostfs/etc/kubernetes/manifests/kube-apiserver.yaml",
    "uid": "etc",
    "filename": "kube-apiserver.yaml",
    "gid": "root"
  }
}

Evaluate entire policy into output.json

opa eval data.main --format pretty -i input.json -b . > output.json

Evaluate findings only

opa eval data.main.findings --format pretty -i input.json -b . > output.json

Example output

{
  "findings": [
    {
      "result": {
        "evaluation": "failed",
        "expected": {
          "filemode": "0644"
        },
        "evidence": {
          "filemode": "0700"
        }
      },
      "rule": {
        "id": "59b5a77b-b090-5630-9a33-73eb805b2d52",
        "name": "Ensure that the API server pod specification file permissions are set to 644 or more restrictive (Automated)",
        "profile_applicability": "* Level 1 - Master Node\n",
        "description": "Ensure that the API server pod specification file has permissions of `644` or more restrictive.\n",
        "rationale": "The API server pod specification file controls various parameters that set the behavior of the API server. You should restrict its file permissions to maintain the integrity of the file. The file should be writable by only the administrators on the system.\n",
        "audit": "Run the below command (based on the file location on your system) on the\nmaster node.\nFor example,\n```\nstat -c %a /etc/kubernetes/manifests/kube-apiserver.yaml\n```\nVerify that the permissions are `644` or more restrictive.\n",
        "remediation": "Run the below command (based on the file location on your system) on the\nmaster node.\nFor example,\n```\nchmod 644 /etc/kubernetes/manifests/kube-apiserver.yaml\n```\n",
        "impact": "None\n",
        "default_value": "By default, the `kube-apiserver.yaml` file has permissions of `640`.\n",
        "references": "1. [https://kubernetes.io/docs/admin/kube-apiserver/](https://kubernetes.io/docs/admin/kube-apiserver/)\n",
        "section": "Master Node Configuration Files",
        "version": 1,
        "tags": [
          "CIS",
          "Kubernetes",
          "CIS 1.1.1",
          "Master Node Configuration Files"
        ],
        "benchmark": {
          "name": "CIS Kubernetes V1.20",
          "version": "v1.0.0"
        }
      }
    },
    {
      "result": {
        "evaluation": "passed",
        "expected": {
          "gid": "root",
          "uid": "root"
        },
        "evidence": {
          "gid": "root",
          "uid": "root"
        }
      },
      "rule": {
        "id": "9f318d4d-2451-574a-99dc-838ed213f09b",
        "name": "Ensure that the API server pod specification file ownership is set toroot:root (Automated)",
        "profile_applicability": "* Level 1 - Master Node\n",
        "description": "Ensure that the API server pod specification file ownership is set to `root:root`.\n",
        "rationale": "The API server pod specification file controls various parameters that set the behavior of the API server. You should set its file ownership to maintain the integrity of the file. The file should be owned by `root:root`.\n",
        "audit": "Run the below command (based on the file location on your system) on the\nmaster node.\nFor example,\n```\nstat -c %U:%G /etc/kubernetes/manifests/kube-apiserver.yaml\n```\nVerify that the ownership is set to `root:root`.\n",
        "remediation": "Run the below command (based on the file location on your system) on the\nmaster node.\nFor example,\n```\nchown root:root /etc/kubernetes/manifests/kube-apiserver.yaml\n```\n",
        "impact": "None\n",
        "default_value": "By default, the `kube-apiserver.yaml` file ownership is set to `root:root`.\n",
        "references": "1. [https://kubernetes.io/docs/admin/kube-apiserver/](https://kubernetes.io/docs/admin/kube-apiserver/)\n",
        "section": "Master Node Configuration Files",
        "version": 1,
        "tags": [
          "CIS",
          "Kubernetes",
          "CIS 1.1.2",
          "Master Node Configuration Files"
        ],
        "benchmark": {
          "name": "CIS Kubernetes V1.20",
          "version": "v1.0.0"
        }
      }
    }
  ],
  "resource": {
    "filename": "kube-apiserver.yaml",
    "gid": "root",
    "mode": "0700",
    "path": "/hostfs/etc/kubernetes/manifests/kube-apiserver.yaml",
    "type": "file",
    "uid": "root"
  }
}

Evaluate with input schema

❯ opa eval data.main --format pretty -i input.json -b . -s compliance/cis_k8s/schemas/input_schema.json
1 error occurred: compliance/lib/data_adapter.rego:11: rego_type_error: undefined ref: input.filenames
        input.filenames
              ^
              have: "filenames"
              want (one of): ["command" "filename" "gid" "mode" "path" "type" "uid"]

Local Testing

Test entire policy

opa build -b ./ -e ./compliance

opa test -b bundle.tar.gz -v

Test specific rule

opa test -v compliance/lib compliance/cis_k8s/test_data.rego compliance/cis_k8s/rules/cis_1_1_2 --ignore="common_tests.rego"

Pre-commit hooks

see pre-commit package

• Install the package brew install pre-commit
• Then run pre-commit install
• Finally pre-commit run --all-files --verbose

Running opa server with the compliance policy

docker run --rm -p 8181:8181 -v $(pwd):/bundle openpolicyagent/opa:0.36.1 run -s -b /bundle

Test it 🚀

curl --location --request POST 'http://localhost:8181/v1/data/main' \
--header 'Content-Type: application/json' \
--data-raw '{
    "input": {
        "resource": {
            "type": "file",
            "mode": "0700",
            "path": "/hostfs/etc/kubernetes/manifests/kube-apiserver.yaml",
            "uid": "etc",
            "filename": "kube-apiserver.yaml",
            "gid": "root"
        }
    }
}'