Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/raspbernetes/k8s-security-policies

This repository offers a comprehensive library of security policies designed to enhance the security of Kubernetes cluster configurations. The policies are developed in accordance with the CIS Kubernetes benchmark.
https://github.com/raspbernetes/k8s-security-policies

benchmark cis cis-kubernetes-benchmark conftest gatekeeper kubernetes kubernetes-clusters kubesec open-policy-agent raspbernetes rego-files rego-policy security violation

Last synced: 24 days ago
JSON representation

This repository offers a comprehensive library of security policies designed to enhance the security of Kubernetes cluster configurations. The policies are developed in accordance with the CIS Kubernetes benchmark.

Awesome Lists containing this project

README 

        



  # Kubernetes Security Policies



  A Comprehensive Library for Fortifying Cluster Configurations.






## Introduction



This repository offers a comprehensive library of security policies designed to fortify Kubernetes cluster configurations. These security policies are derived from the [CIS Kubernetes benchmark]((https://cloud.google.com/kubernetes-engine/docs/concepts/cis-benchmarks)) and rules specified by [Kubesec.io](https://kubesec.io/). The policies are crafted in REGO, a high-level declarative language tailored for defining policies over intricate hierarchical data structures. For an in-depth understanding of REGO, refer to the [Policy Language](https://www.openpolicyagent.org/docs/latest/policy-language/) documentation.



## Why use Kubernetes Security Policies?



Kubernetes Security Policies are crucial for:



1. **Enhancing Security**: They protect clusters against threats, misconfigurations, and vulnerabilities by applying predefined rules and best practices.



2. **Ensuring Consistency**: Policies enforce standardized configurations across clusters, simplifying management and reducing configuration drift.



3. **Maintaining Compliance**: By implementing established benchmarks like CIS Kubernetes, policies help adhere to industry-specific regulatory requirements.



4. **Automating Enforcement**: Policies automate the enforcement of security best practices, reducing human error and streamlining deployments.



5. **Simplifying Auditing**: They provide a clear approach to defining and enforcing configurations, enabling easier auditing and monitoring of clusters.



Kubernetes Security Policies are essential for a robust security strategy and promoting a proactive security culture within organizations.



## Repository Structure



The `policies` directory houses numerous folders, each representing a distinct policy. Folders are named according to the benchmark standard, followed by a number to ensure differentiation. For instance, the `1.2.1 Ensure that the --anonymous-auth argument is set to false` policy from the CIS benchmark is verified by REGO files located in the `CIS1.2.1` directory. To explore each policy further, consult the [Policy Inventory](policies/POLICIES.md).



Within each folder, you will find a `.rego` file and a unit test `.rego` file. Additionally, there is a separate `lib` folder containing two .rego files that feature general functions importable into other `.rego` files. The `kubernetes.rego` file encompasses functions and rules employed in security control `.rego` files, while the `test.rego` file houses functions that can be imported into unit test files.



## Policy Implementation Process



### Identifying Violations



Each REGO policy examines the manifests of resources deployable in a Kubernetes cluster. The `violation` block in each policy file typically includes:



* Identifying the resource object being examined and returning it.

* Verifying if the object breaches the controls defined in the benchmark.

* Displaying an error message if a violation is detected.



Here's a simplified example of a violation:



```rego

violation[msg] {

    kubernetes.pods[pod]

    not kubernetes.contains_element(params.allowedDeploymentsOrPods, kubernetes.name)

    is_automount_serviceaccount_token_enabled(pod)

    msg := kubernetes.format(sprintf("%v: %v - Automount Service account token must be set to false", [kubernetes.kind, kubernetes.name]))

}

```



The `kubernetes.` prefix indicates a function call from `kubernetes.rego`, which contains general functions. Control-specific logic is written in the corresponding REGO file.



### Configuring Parameters



Security policies use parameters to evaluate resources. These parameters can be external (e.g., defined in Gatekeeper `constraints`) or embedded as default values within the file. Parameters are standardized by combining them:



```rego

params = object.union(default_parameters, kubernetes.parameters)

```



### Testing Policies



To validate policy accuracy, the `OPA` testing [framework](https://www.openpolicyagent.org/docs/v0.12.2/how-do-i-test-policies/) is used. Each unit test includes functions prefixed with `test` in the name, enabling `opa test` to recognize them. Positive cases start with `test_no_violation` and negative cases with `test_violation`. Tests use `policy_input` formatted like the manifests:



```rego

test_violation {

    test.violations(violation) with input as policy_input(true)

}



test_no_violation {

    test.no_violations(violation) with input as policy_input(false)

}

```



Unit test files share the same package as the REGO policy, ensuring the test verifies policy input against the violation block within the same package.



The `opa test` output displays whether all tests passed:



```rego

$ opa test policies -v

data.spec_volumes_hostpath_path_var_run_docker_sock.test_no_violation: PASS (318.786µs)

data.containers_image_tag.test_violation_1: PASS (512.689µs)

data.containers_image_tag.test_violation_2: PASS (515.964µs)

data.containers_image_tag.test_no_violation: PASS (389.822µs)

data.containers_securitycontext_allowprivilegedeescalation_true.test_violation: PASS (474.668µs)

data.containers_securitycontext_allowprivilegedeescalation_true.test_no_violation: PASS (361.12µs)

--------------------------------------------------------------------------------

PASS: 5/5

```



## Integration with Policy Enforcement Tools



This policy library is designed to be compatible with various tools, such as Conftest and Gatekeeper.



### Gatekeeper



Rego policies can serve as a schema in Gatekeeper `ConstraintTemplate`. Based on the template, `constraints` can be deployed onto Kubernetes clusters to monitor `CREATE` and `UPDATE` operations against the API server. Gatekeeper also offers `AUDIT` functionality to evaluate existing resources against the `constraints`. To learn more about creating `constraints`, visit the [Gatekeeper](https://github.com/open-policy-agent/gatekeeper) repository.



### Conftest



Conftest enables the evaluation of structured YAML manifest files intended for deployment to your clusters. To use Conftest, first install [Conftest](https://github.com/open-policy-agent/conftest) and then run `conftest test` on a YAML file against the policy library:



```shell

$ conftest test deployment.yaml -p policies/. --all-namespaces

```



The output indicates whether the tests have passed. Here's an example:



```log

FAIL - deployment.yaml - Containers must not run as root

FAIL - deployment.yaml - Deployments are not allowed



2 tests, 0 passed, 0 warnings, 2 failure

```