kube-bench is a Go application that checks whether Kubernetes is deployed securely by running the checks documented in the CIS Kubernetes Benchmark.
Note that it is impossible to inspect the master nodes of managed clusters, e.g. GKE, EKS and AKS, using kube-bench as one does not have access to such nodes, although it is still possible to use kube-bench to check worker node configuration in these environments.
Tests are configured with YAML files, making this tool easy to update as test specifications evolve.
Table of Contents
- Table of Contents
- CIS Kubernetes Benchmark support
- Running kube-bench
- Running on OpenShift
- Test config YAML representation
- Testing locally with kind
CIS Kubernetes Benchmark support
kube-bench supports the tests for Kubernetes as defined in the CIS Benchmarks 1.3.0 to 1.5.0 respectively.
|CIS Kubernetes Benchmark||kube-bench config||Kubernetes versions|
By default, kube-bench will determine the test set to run based on the Kubernetes version running on the machine.
There is also preliminary support for Red Hat's OpenShift Hardening Guide for 3.10 and 3.11. Please note that kube-bench does not automatically detect OpenShift - see below.
You can choose to
- run kube-bench from inside a container (sharing PID namespace with the host)
- run a container that installs kube-bench on the host, and then run kube-bench directly on the host
- install the latest binaries from the Releases page,
- compile it from source.
If you run kube-bench directly from the command line you may need to be root / sudo to have access to all the config files.
kube-bench automatically selects which
controls to use based on the detected
node type and the version of Kubernetes a cluster is running. This behavior
can be overridden by specifying the
node subcommand and the
--version flag on the command line.
The Kubernetes version can also be set with the
KUBE_BENCH_VERSION environment variable.
The value of
--version takes precedence over the value of
For example, run kube-bench against a master with version auto-detection:
Or run kube-bench against a worker node using the tests for Kubernetes version 1.13:
kube-bench node --version 1.13
kube-bench will map the
--version to the corresponding CIS Benchmark version as indicated by the mapping table above. For example, if you specify
--version 1.13, this is mapped to CIS Benchmark version
Alternatively, you can specify
--benchmark to run a specific CIS Benchmark version:
kube-bench node --benchmark cis-1.4
If you want to target specific CIS Benchmark
target (i.e master, node, etcd, etc...)
you can use the
run --targets subcommand.
kube-bench --benchmark cis-1.4 run --targets master,node
kube-bench --benchmark cis-1.5 run --targets master,node,etcd,policies
The following table shows the valid targets based on the CIS Benchmark version. | CIS Benchmark | Targets | |---|---| | cis-1.3| master, node | | cis-1.4| master, node | | cis-1.5| master, controlplane, node, etcd, policies |
If no targets are specified,
kube-bench will determine the appropriate targets based on the CIS Benchmark version.
controls for the various versions of CIS Benchmark can be found in directories
with same name as the CIS Benchmark versions under
cfg/, for example
It is an error to specify both --version and --benchmark flags together
Running inside a container
You can avoid installing kube-bench on the host by running it inside a container using the host PID namespace and mounting the
/var directories where the configuration and other files are located on the host so that kube-bench can check their existence and permissions.
docker run --pid=host -v /etc:/etc:ro -v /var:/var:ro -t aquasec/kube-bench:latest [master|node] --version 1.13
Note: the tests require either the kubelet or kubectl binary in the path in order to auto-detect the Kubernetes version. You can pass
-v $(which kubectl):/usr/bin/kubectlto resolve this. You will also need to pass in kubeconfig credentials. For example:
docker run --pid=host -v /etc:/etc:ro -v /var:/var:ro -v $(which kubectl):/usr/bin/kubectl -v ~/.kube:/.kube -e KUBECONFIG=/.kube/config -t aquasec/kube-bench:latest [master|node]
You can use your own configs by mounting them over the default ones in
docker run --pid=host -v /etc:/etc:ro -v /var:/var:ro -t -v path/to/my-config.yaml:/opt/kube-bench/cfg/config.yam -v $(which kubectl):/usr/bin/kubectl -v ~/.kube:/.kube -e KUBECONFIG=/.kube/config aquasec/kube-bench:latest [master|node]
Running in a Kubernetes cluster
You can run kube-bench inside a pod, but it will need access to the host's PID namespace in order to check the running processes, as well as access to some directories on the host where config files and other files are stored.
Master nodes are automatically detected by kube-bench and will run master checks when possible. The detection is done by verifying that mandatory components for master, as defined in the config files, are running (see Configuration).
job.yaml file can be applied to run the tests as a job. For example:
$ kubectl apply -f job.yaml job.batch/kube-bench created $ kubectl get pods NAME READY STATUS RESTARTS AGE kube-bench-j76s9 0/1 ContainerCreating 0 3s # Wait for a few seconds for the job to complete $ kubectl get pods NAME READY STATUS RESTARTS AGE kube-bench-j76s9 0/1 Completed 0 11s # The results are held in the pod's logs kubectl logs kube-bench-j76s9 [INFO] 1 Master Node Security Configuration [INFO] 1.1 API Server ...
You can still force to run specific master or node checks using respectively
To run the tests on the master node, the pod needs to be scheduled on that node. This involves setting a nodeSelector and tolerations in the pod spec.
The default labels applied to master nodes has changed since Kubernetes 1.11, so if you are using an older version you may need to modify the nodeSelector and tolerations to run the job on the master node.
Running in an EKS cluster
There is a
job-eks.yaml file for running the kube-bench node checks on an EKS cluster. The significant difference on EKS is that it's not possible to schedule jobs onto the master node, so master checks can't be performed
- To create an EKS Cluster refer to Getting Started with Amazon EKS in the Amazon EKS User Guide
- Information on configuring
kubectland the AWS CLI is within
- Create an Amazon Elastic Container Registry (ECR) repository to host the kube-bench container image
aws ecr create-repository --repository-name k8s/kube-bench --image-tag-mutability MUTABLE
- Download, build and push the kube-bench container image to your ECR repo
git clone https://github.com/aquasecurity/kube-bench.git $(aws ecr get-login --no-include-email --region <AWS_REGION>) docker build -t k8s/kube-bench . docker tag k8s/kube-bench:latest <AWS_ACCT_NUMBER>.dkr.ecr.<AWS_REGION>.amazonaws.com/k8s/kube-bench:latest docker tag k8s/kube-bench:latest <AWS_ACCT_NUMBER>.dkr.ecr.<AWS_REGION>.amazonaws.com/k8s/kube-bench:latest docker push <AWS_ACCT_NUMBER>.dkr.ecr.<AWS_REGION>.amazonaws.com/k8s/kube-bench:latest
- Copy the URI of your pushed image, the URI format is like this:
- Replace the
job-eks.yamlwith the URI from Step 4
- Run the kube-bench job on a Pod in your Cluster:
kubectl apply -f job-eks.yaml
- Find the Pod that was created, it should be in the
kubectl get pods --all-namespaces
- Retrieve the value of this Pod and output the report, note the Pod name will vary:
kubectl logs kube-bench-<value>
- You can save the report for later reference:
kubectl logs kube-bench-<value> > kube-bench-report.txt
Installing from a container
This command copies the kube-bench binary and configuration files to your host from the Docker container: ** binaries compiled for linux-x86-64 only (so they won't run on macOS or Windows) **
docker run --rm -v `pwd`:/host aquasec/kube-bench:latest install
You can then run
Installing from sources
If Go is installed on the target machines, you can simply clone this repository and run as follows (assuming your
GOPATH is set):
go get github.com/aquasecurity/kube-bench go get github.com/golang/dep/cmd/dep cd $GOPATH/src/github.com/aquasecurity/kube-bench $GOPATH/bin/dep ensure -vendor-only go build -o kube-bench . # See all supported options ./kube-bench --help # Run all checks ./kube-bench
Running on OpenShift
| OpenShift Hardening Guide | kube-bench config | |---|---|---| | ocp-3.10| rh-0.7 | | ocp-3.11| rh-0.7 |
kube-bench includes a set of test files for Red Hat's OpenShift hardening guide for OCP 3.10 and 3.11. To run this you will need to specify
--benchmark rh-07, or
--version ocp-3.10 or
when you run the
kube-bench command (either directly or through YAML).
There are three output states:
- [PASS] and [FAIL] indicate that a test was run successfully, and it either passed or failed.
- [WARN] means this test needs further attention, for example it is a test that needs to be run manually.
- [INFO] is informational output that needs no further action.
- If the test is Manual, this always generates WARN (because the user has to run it manually)
- If the test is Scored, and kube-bench was unable to run the test, this generates FAIL (because the test has not been passed, and as a Scored test, if it doesn't pass then it must be considered a failure).
- If the test is Not Scored, and kube-bench was unable to run the test, this generates WARN.
- If the test is Scored, type is empty, and there are no
test_itemspresent, it generates a WARN.
Kubernetes configuration and binary file locations and names can vary from installation to installation, so these are configurable in the
Any settings in the version-specific config file
cfg/<version>/config.yaml take precedence over settings in the main
You can read more about
kube-bench configuration in our documentation.
Test config YAML representation
The tests (or "controls") are represented as YAML documents (installed by default into
./cfg). There are different versions of these test YAML files reflecting different versions of the CIS Kubernetes Benchmark. You will find more information about the test file YAML definitions in our documentation.
If you decide that a recommendation is not appropriate for your environment, you can choose to omit it by editing the test YAML file to give it the check type
skip as in this example:
checks: - id: 2.1.1 text: "Ensure that the --allow-privileged argument is set to false (Scored)" type: "skip" scored: true
No tests will be run for this check and the output will be marked [INFO].
Going forward we plan to release updates to kube-bench to add support for new releases of the Benchmark, which in turn we can anticipate being made for each new Kubernetes release.
We welcome PRs and issue reports.
Testing locally with kind
Our makefile contains targets to test your current version of kube-bench inside a Kind cluster. This can be very handy if you don't want to run a real Kubernetes cluster for development purposes.
First, you'll need to create the cluster using
make kind-test-cluster this will create a new cluster if it cannot be found on your machine. By default, the cluster is named
kube-bench but you can change the name by using the environment variable
If kind cannot be found on your system the target will try to install it using
Next, you'll have to build the kube-bench docker image using
make build-docker, then we will be able to push the docker image to the cluster using
Finally, we can use the
make kind-run target to run the current version of kube-bench in the cluster and follow the logs of pods created. (Ctrl+C to exit)
Every time you want to test a change, you'll need to rebuild the docker image and push it to cluster before running it again. (
make build-docker kind-push kind-run )
If you think you have found a bug please follow the instructions below.
- Please spend a small amount of time giving due diligence to the issue tracker. Your issue might be a duplicate.
- Open a new issue if a duplicate doesn't already exist.
- Note the version of kube-bench you are running (from
kube-bench version) and the command line options you are using.
- Note the version of Kubernetes you are running (from
oc versionfor OpenShift).
-v 10command line option and save the log output. Please paste this into your issue.
- Remember users might be searching for your issue in the future, so please give it a meaningful title to help others.
We also use the GitHub issue tracker to track feature requests. If you have an idea to make kube-bench even more awesome follow the steps below.
- Open a new issue.
- Remember users might be searching for your issue in the future, so please give it a meaningful title to helps others.
- Clearly define the use case, using concrete examples. For example, I type
thisand kube-bench does
- If you would like to include a technical design for your feature please feel free to do so.
We welcome pull requests!
- Your PR is more likely to be accepted if it focuses on just one change.
- Please include a comment with the results before and after your change.
- Your PR is more likely to be accepted if it includes tests. (We have not historically been very strict about tests, but we would like to improve this!).
- You're welcome to submit a draft PR if you would like early feedback on an idea or an approach.
- Happy coding!