Kube Hunter

What is kube-hunter?

kube-hunter hunts for security weaknesses in Kubernetes clusters. The tool was developed to increase awareness and visibility for security issues in Kubernetes environments. You should NOT run kube-hunter on a Kubernetes cluster that you don't own!

To learn more about the kube-hunter scanner itself visit kube-hunter GitHub or kube-hunter Website.

Deployment

The kube-hunter chart can be deployed via helm:

# Install HelmChart (use -n to configure another namespace)
helm upgrade --install kube-hunter secureCodeBox/kube-hunter

Scanner Configuration

The following security scan configuration example are based on the kube-hunter Documentation, please take a look at the original documentation for more configuration examples.

To specify remote machines for hunting, select option 1 or use the --remote option. Example: kube-hunter --remote some.node.com
To specify interface scanning, you can use the --interface option (this will scan all the machine's network interfaces). Example: kube-hunter --interface
To specify a specific CIDR to scan, use the --cidr option. Example: kube-hunter --cidr 192.168.0.0/24

Requirements

Kubernetes: >=v1.11.0-0

Values

Key	Type	Default	Description
cascadingRules.enabled	bool	`true`	Enables or disables the installation of the default cascading rules for this scanner
parser.affinity	object	`{}`	Optional affinity settings that control how the parser job is scheduled (see: https://kubernetes.io/docs/tasks/configure-pod-container/assign-pods-nodes-using-node-affinity/)
parser.env	list	`[]`	Optional environment variables mapped into each parseJob (see: https://kubernetes.io/docs/tasks/inject-data-application/define-environment-variable-container/)
parser.image.pullPolicy	string	`"IfNotPresent"`	Image pull policy. One of Always, Never, IfNotPresent. Defaults to Always if :latest tag is specified, or IfNotPresent otherwise. More info: https://kubernetes.io/docs/concepts/containers/images#updating-images
parser.image.repository	string	`"docker.io/securecodebox/parser-kube-hunter"`	Parser image repository
parser.image.tag	string	defaults to the charts version	Parser image tag
parser.scopeLimiterAliases	object	`{}`	Optional finding aliases to be used in the scopeLimiter.
parser.tolerations	list	`[]`	Optional tolerations settings that control how the parser job is scheduled (see: https://kubernetes.io/docs/concepts/scheduling-eviction/taint-and-toleration/)
parser.ttlSecondsAfterFinished	string	`nil`	seconds after which the kubernetes job for the parser will be deleted. Requires the Kubernetes TTLAfterFinished controller: https://kubernetes.io/docs/concepts/workloads/controllers/ttlafterfinished/
scanner.activeDeadlineSeconds	string	`nil`	There are situations where you want to fail a scan Job after some amount of time. To do so, set activeDeadlineSeconds to define an active deadline (in seconds) when considering a scan Job as failed. (see: https://kubernetes.io/docs/concepts/workloads/controllers/job/#job-termination-and-cleanup)
scanner.affinity	object	`{}`	Optional affinity settings that control how the scanner job is scheduled (see: https://kubernetes.io/docs/tasks/configure-pod-container/assign-pods-nodes-using-node-affinity/)
scanner.backoffLimit	int	3	There are situations where you want to fail a scan Job after some amount of retries due to a logical error in configuration etc. To do so, set backoffLimit to specify the number of retries before considering a scan Job as failed. (see: https://kubernetes.io/docs/concepts/workloads/controllers/job/#pod-backoff-failure-policy)
scanner.env	list	`[]`	Optional environment variables mapped into each scanJob (see: https://kubernetes.io/docs/tasks/inject-data-application/define-environment-variable-container/)
scanner.extraContainers	list	`[]`	Optional additional Containers started with each scanJob (see: https://kubernetes.io/docs/concepts/workloads/pods/init-containers/)
scanner.extraVolumeMounts	list	`[]`	Optional VolumeMounts mapped into each scanJob (see: https://kubernetes.io/docs/concepts/storage/volumes/)
scanner.extraVolumes	list	`[]`	Optional Volumes mapped into each scanJob (see: https://kubernetes.io/docs/concepts/storage/volumes/)
scanner.image.pullPolicy	string	`"IfNotPresent"`	Image pull policy. One of Always, Never, IfNotPresent. Defaults to Always if :latest tag is specified, or IfNotPresent otherwise. More info: https://kubernetes.io/docs/concepts/containers/images#updating-images
scanner.image.repository	string	`"docker.io/securecodebox/scanner-kube-hunter"`	Container Image to run the scan
scanner.image.tag	string	`nil`	defaults to the charts appVersion
scanner.nameAppend	string	`nil`	append a string to the default scantype name.
scanner.resources	object	`{}`	CPU/memory resource requests/limits (see: https://kubernetes.io/docs/tasks/configure-pod-container/assign-memory-resource/, https://kubernetes.io/docs/tasks/configure-pod-container/assign-cpu-resource/)
scanner.securityContext	object	`{"allowPrivilegeEscalation":false,"capabilities":{"drop":["all"]},"privileged":false,"readOnlyRootFilesystem":true,"runAsNonRoot":false}`	Optional securityContext set on scanner container (see: https://kubernetes.io/docs/tasks/configure-pod-container/security-context/)
scanner.securityContext.allowPrivilegeEscalation	bool	`false`	Ensure that users privileges cannot be escalated
scanner.securityContext.capabilities.drop[0]	string	`"all"`	This drops all linux privileges from the container.
scanner.securityContext.privileged	bool	`false`	Ensures that the scanner container is not run in privileged mode
scanner.securityContext.readOnlyRootFilesystem	bool	`true`	Prevents write access to the containers file system
scanner.securityContext.runAsNonRoot	bool	`false`	Enforces that the scanner image is run as a non root user
scanner.tolerations	list	`[]`	Optional tolerations settings that control how the scanner job is scheduled (see: https://kubernetes.io/docs/concepts/scheduling-eviction/taint-and-toleration/)
scanner.ttlSecondsAfterFinished	string	`nil`	seconds after which the kubernetes job for the scanner will be deleted. Requires the Kubernetes TTLAfterFinished controller: https://kubernetes.io/docs/concepts/workloads/controllers/ttlafterfinished/

License

Code of secureCodeBox is licensed under the Apache License 2.0.

Examples

in-cluster

Scan
Findings

# SPDX-FileCopyrightText: the secureCodeBox authors
#
# SPDX-License-Identifier: Apache-2.0

apiVersion: "execution.securecodebox.io/v1"
kind: Scan
metadata:
  name: "kube-hunter-in-cluster"
spec:
  scanType: "kube-hunter"
  parameters:
    - "--pod"

# SPDX-FileCopyrightText: the secureCodeBox authors
#
# SPDX-License-Identifier: Apache-2.0

{
    "nodes": [
        {
            "type": "Node/Master",
            "location": "10.0.0.1"
        },
        {
            "type": "Node/Master",
            "location": "10.96.0.1"
        }
    ],
    "services": [
        {
            "service": "Kubelet API",
            "location": "10.0.0.1:10250",
            "description": "The Kubelet is the main component in every Node, all pod operations goes through the kubelet"
        },
        {
            "service": "Metrics Server",
            "location": "10.0.0.1:6443",
            "description": "The Metrics server is in charge of providing resource usage metrics for pods and nodes to the API server."
        },
        {
            "service": "API Server",
            "location": "10.96.0.1:443",
            "description": "The API server is in charge of all operations on the cluster."
        }
    ],
    "vulnerabilities": [
        {
            "location": "Local to Pod(scan-kube-hunter-in-cluster-4rfff)",
            "vid": "KHV050",
            "category": "Access Risk",
            "severity": "low",
            "vulnerability": "Read access to pod's service account token",
            "description": " Accessing the pod service account token gives an attacker the option to use the server API ",
            "evidence": "eyJhbGciOiJSUzI1NiIsImtpZCI6IkNabmY2NVgxUmR1ZnQzbHJVQVAzZFFUNjBiR0hUVE9SRDNPcURyenlkODgifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJkZWZhdWx0Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZWNyZXQubmFtZSI6Imx1cmNoZXItdG9rZW4tcGpmNGIiLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlcnZpY2UtYWNjb3VudC5uYW1lIjoibHVyY2hlciIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50LnVpZCI6IjUzOGVhYjdmLTY1YjAtNDE4Yy04MGI2LTI1NGQxNDQ4ODU3NiIsInN1YiI6InN5c3RlbTpzZXJ2aWNlYWNjb3VudDpkZWZhdWx0Omx1cmNoZXIifQ.cGtQHagQ2xxlAFnWwFRNgGJIkaeZIKnqoYYb8GmxN94ry0wwxCbgBm4Kg33A903wDBxd8iuITTk-r8UPZyYJHoxlVu0pHt-3SAc4NT0ob50R2acVXQ2qj_yJOOQHurCWeOJMkGqtCyUoZ8Xcnc6z32Ao-NWzKD-0wV7ndpKm-ytHP0YpHb9bLUPcQGvFoh_UF132yjeJqzwLPRX6hStMYOa8LNhJGyhdejW3BIOylzVPNkKE5lEjWv9f853qnTKG-TzXHBbth7qV8UHwSoY8YFoMezK3zazQt4dN1VG_wYmZ0ujikTC7TRTGr500kFxfpACKwdQ1M1fXgKJhNv9UgA",
            "hunter": "Access Secrets"
        },
        {
            "location": "Local to Pod(scan-kube-hunter-in-cluster-4rfff)",
            "vid": "None",
            "category": "Access Risk",
            "severity": "low",
            "vulnerability": "CAP_NET_RAW Enabled",
            "description": "CAP_NET_RAW is enabled by default for pods. If an attacker manages to compromise a pod, they could potentially take advantage of this capability to perform network attacks on other pods running on the same node",
            "evidence": "",
            "hunter": "Pod Capabilities Hunter"
        },
        {
            "location": "Local to Pod(scan-kube-hunter-in-cluster-4rfff)",
            "vid": "None",
            "category": "Access Risk",
            "severity": "low",
            "vulnerability": "Access to pod's secrets",
            "description": " Accessing the pod's secrets within a compromised pod might disclose valuable data to a potential attacker",
            "evidence": "['/var/run/secrets/kubernetes.io/serviceaccount/namespace', '/var/run/secrets/kubernetes.io/serviceaccount/ca.crt', '/var/run/secrets/kubernetes.io/serviceaccount/token', '/var/run/secrets/kubernetes.io/serviceaccount/..2020_04_03_14_52_24.460746409/ca.crt', '/var/run/secrets/kubernetes.io/serviceaccount/..2020_04_03_14_52_24.460746409/token', '/var/run/secrets/kubernetes.io/serviceaccount/..2020_04_03_14_52_24.460746409/namespace']",
            "hunter": "Access Secrets"
        },
        {
            "location": "10.96.0.1:443",
            "vid": "KHV002",
            "category": "Information Disclosure",
            "severity": "medium",
            "vulnerability": "K8s Version Disclosure",
            "description": "The kubernetes version could be obtained from the /version endpoint ",
            "evidence": "v1.18.0",
            "hunter": "Api Version Hunter"
        },
        {
            "location": "10.96.0.1:443",
            "vid": "KHV005",
            "category": "Information Disclosure",
            "severity": "medium",
            "vulnerability": "Access to API using service account token",
            "description": " The API Server port is accessible. Depending on your RBAC settings this could expose access to or control of your cluster. ",
            "evidence": "b'{\"kind\":\"APIVersions\",\"versions\":[\"v1\"],\"serverAddressByClientCIDRs\":[{\"clientCIDR\":\"0.0.0.0/0\",\"serverAddress\":\"172.17.0.2:6443\"}]}\\n'",
            "hunter": "API Server Hunter"
        }
    ],
    "kburl": "https://aquasecurity.github.io/kube-hunter/kb/{vid}"
}

What is kube-hunter?​

Deployment​

Scanner Configuration​

Requirements​

Values​

License​

Examples​

in-cluster​