Kubernetes Security Technical Implementation Guide

Version

CNTR-K8-000150

Vuln IDs

V-242376

Rule IDs

SV-242376r863952_rule

The Kubernetes Controller Manager will prohibit the use of SSL and unauthorized versions of TLS protocols to properly secure communication. The use of unsupported protocol exposes vulnerabilities to the Kubernetes by rogue traffic interceptions, man-in-the-middle attacks, and impersonation of users or services from the container platform runtime, registry, and key store. To enable the minimum version of TLS to be used by the Kubernetes Controller Manager, the setting "tls-min-version" must be set.

Checks: C-45651r863731_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i tls-min-version * If the setting "tls-min-version" is not configured in the Kubernetes Controller Manager manifest file or it is set to "VersionTLS10" or "VersionTLS11", this is a finding.

Fix: F-45609r863732_fix

Edit the Kubernetes Controller Manager manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--tls-min-version" to "VersionTLS12" or higher.

b

The Kubernetes Scheduler must use TLS 1.2, at a minimum, to protect the confidentiality of sensitive data during electronic dissemination.

AC-17 - Medium - CCI-000068 - V-242377 - SV-242377r863953_rule

RMF Control

AC-17

Severity

M

CCI

Version

CNTR-K8-000160

Vuln IDs

V-242377

Rule IDs

SV-242377r863953_rule

The Kubernetes Scheduler will prohibit the use of SSL and unauthorized versions of TLS protocols to properly secure communication. The use of unsupported protocol exposes vulnerabilities to the Kubernetes by rogue traffic interceptions, man-in-the-middle attacks, and impersonation of users or services from the container platform runtime, registry, and keystore. To enable the minimum version of TLS to be used by the Kubernetes API Server, the setting "tls-min-version" must be set.

Checks: C-45652r863734_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i tls-min-version * If the setting "tls-min-version" is not configured in the Kubernetes Scheduler manifest file or it is set to "VersionTLS10" or "VersionTLS11", this is a finding.

Fix: F-45610r863735_fix

Edit the Kubernetes Scheduler manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--tls-min-version" to "VersionTLS12" or higher.

b

The Kubernetes API Server must use TLS 1.2, at a minimum, to protect the confidentiality of sensitive data during electronic dissemination.

AC-17 - Medium - CCI-000068 - V-242378 - SV-242378r863954_rule

RMF Control

AC-17

Severity

M

CCI

Version

CNTR-K8-000170

Vuln IDs

V-242378

Rule IDs

SV-242378r863954_rule

The Kubernetes API Server will prohibit the use of SSL and unauthorized versions of TLS protocols to properly secure communication. The use of unsupported protocol exposes vulnerabilities to the Kubernetes by rogue traffic interceptions, man-in-the-middle attacks, and impersonation of users or services from the container platform runtime, registry, and keystore. To enable the minimum version of TLS to be used by the Kubernetes API Server, the setting "tls-min-version" must be set.

Checks: C-45653r863737_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i tls-min-version * If the setting "tls-min-version" is not configured in the Kubernetes API Server manifest file or it is set to "VersionTLS10" or "VersionTLS11", this is a finding.

Fix: F-45611r863738_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--tls-min-version" to "VersionTLS12" or higher.

b

The Kubernetes etcd must use TLS to protect the confidentiality of sensitive data during electronic dissemination.

AC-17 - Medium - CCI-000068 - V-242379 - SV-242379r863955_rule

RMF Control

AC-17

Severity

M

CCI

Version

CNTR-K8-000180

Vuln IDs

V-242379

Rule IDs

SV-242379r863955_rule

Kubernetes etcd will prohibit the use of SSL and unauthorized versions of TLS protocols to properly secure communication. The use of unsupported protocol exposes vulnerabilities to the Kubernetes by rogue traffic interceptions, man-in-the-middle attacks, and impersonation of users or services from the container platform runtime, registry, and keystore. To enable the minimum version of TLS to be used by the Kubernetes API Server, the setting "auto-tls" must be set.

Checks: C-45654r863740_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i auto-tls * If the setting "auto-tls" is not configured in the Kubernetes etcd manifest file or it is set to true, this is a finding.

Fix: F-45612r863741_fix

Edit the Kubernetes etcd manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "-auto-tls" to "false".

b

The Kubernetes etcd must use TLS to protect the confidentiality of sensitive data during electronic dissemination.

AC-17 - Medium - CCI-000068 - V-242380 - SV-242380r863956_rule

RMF Control

AC-17

Severity

M

CCI

Version

CNTR-K8-000190

Vuln IDs

V-242380

Rule IDs

SV-242380r863956_rule

The Kubernetes API Server will prohibit the use of SSL and unauthorized versions of TLS protocols to properly secure communication. The use of unsupported protocol exposes vulnerabilities to the Kubernetes by rogue traffic interceptions, man-in-the-middle attacks, and impersonation of users or services from the container platform runtime, registry, and keystore. To enable the minimum version of TLS to be used by the Kubernetes API Server, the setting "peer-auto-tls" must be set.

Checks: C-45655r863743_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -I peer-auto-tls * If the setting "peer-auto-tls" is not configured in the Kubernetes etcd manifest file or it is set to "true", this is a finding.

Fix: F-45613r863744_fix

Edit the Kubernetes etcd manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "peer-auto-tls" to "false".

c

The Kubernetes Controller Manager must create unique service accounts for each work payload.

AC-2 - High - CCI-000015 - V-242381 - SV-242381r863957_rule

RMF Control

AC-2

Severity

H

CCI

CCI-000015

Version

CNTR-K8-000220

Vuln IDs

V-242381

Rule IDs

SV-242381r863957_rule

The Kubernetes Controller Manager is a background process that embeds core control loops regulating cluster system state through the API Server. Every process executed in a pod has an associated service account. By default, service accounts use the same credentials for authentication. Implementing the default settings poses a High risk to the Kubernetes Controller Manager. Setting the use-service-account-credential value lowers the attack surface by generating unique service accounts settings for each controller instance.

Checks: C-45656r863746_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i use-service-account-credentials * If the setting use-service-account-credentials is not configured in the Kubernetes Controller Manager manifest file or it is set to "false", this is a finding.

Fix: F-45614r863747_fix

Edit the Kubernetes Controller Manager manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "use-service-account-credentials" to "true".

b

The Kubernetes API Server must enable Node,RBAC as the authorization mode.

AC-3 - Medium - CCI-000213 - V-242382 - SV-242382r863958_rule

RMF Control

AC-3

Severity

M

CCI

Version

CNTR-K8-000270

Vuln IDs

V-242382

Rule IDs

SV-242382r863958_rule

To mitigate the risk of unauthorized access to sensitive information by entities that have been issued certificates by DoD-approved PKIs, all DoD systems (e.g., networks, web servers, and web portals) must be properly configured to incorporate access control methods that do not rely solely on the possession of a certificate for access. Successful authentication must not automatically give an entity access to an asset or security boundary. Authorization procedures and controls must be implemented to ensure each authenticated entity also has a validated and current authorization. Authorization is the process of determining whether an entity, once authenticated, is permitted to access a specific asset. Node,RBAC is the method within Kubernetes to control access of users and applications. Kubernetes uses roles to grant authorization API requests made by kubelets. Satisfies: SRG-APP-000033-CTR-000090, SRG-APP-000033-CTR-000095

Checks: C-45657r863749_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: "grep -i authorization-mode *" If the setting "authorization-mode" is not configured in the Kubernetes API Server manifest file or is not set to "Node,RBAC", this is a finding.

Fix: F-45615r863750_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--authorization-mode" to "Node,RBAC".

c

User-managed resources must be created in dedicated namespaces.

CM-6 - High - CCI-000366 - V-242383 - SV-242383r863959_rule

RMF Control

CM-6

Severity

H

CCI

Version

CNTR-K8-000290

Vuln IDs

V-242383

Rule IDs

SV-242383r863959_rule

Creating namespaces for user-managed resources is important when implementing Role-Based Access Controls (RBAC). RBAC allows for the authorization of users and helps support proper API server permissions separation and network micro segmentation. If user-managed resources are placed within the default namespaces, it becomes impossible to implement policies for RBAC permission, service account usage, network policies, and more.

Checks: C-45658r863752_chk

To view the available namespaces, run the command: kubectl get namespaces The default namespaces to be validated are default, kube-public, and kube-node-lease if it is created. For the default namespace, execute the commands: kubectl config set-context --current --namespace=default kubectl get all For the kube-public namespace, execute the commands: kubectl config set-context --current --namespace=kube-public kubectl get all For the kube-node-lease namespace, execute the commands: kubectl config set-context --current --namespace=kube-node-lease kubectl get all The only valid return values are the kubernetes service (i.e., service/kubernetes) and nothing at all. If a return value is returned from the "kubectl get all" command and it is not the kubernetes service (i.e., service/kubernetes), this is a finding.

Fix: F-45616r863753_fix

Move any user-managed resources from the default, kube-public, and kube-node-lease namespaces to user namespaces.

b

The Kubernetes Scheduler must have secure binding.

AC-3 - Medium - CCI-000213 - V-242384 - SV-242384r863960_rule

RMF Control

AC-3

Severity

M

CCI

Version

CNTR-K8-000300

Vuln IDs

V-242384

Rule IDs

SV-242384r863960_rule

Limiting the number of attack vectors and implementing authentication and encryption on the endpoints available to external sources is paramount when securing the overall Kubernetes cluster. The Scheduler API service exposes port 10251/TCP by default for health and metrics information use. This port does not encrypt or authenticate connections. If this port is exposed externally, an attacker can use this port to attack the entire Kubernetes cluster. By setting the bind address to localhost (i.e., 127.0.0.1), only those internal services that require health and metrics information can access the Scheduler API.

Checks: C-45659r863755_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i bind-address * If the setting "bind-address" is not set to "127.0.0.1" or is not found in the Kubernetes Scheduler manifest file, this is a finding.

Fix: F-45617r863756_fix

Edit the Kubernetes Scheduler manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the argument "--bind-address" to "127.0.0.1".

b

The Kubernetes Controller Manager must have secure binding.

AC-3 - Medium - CCI-000213 - V-242385 - SV-242385r863961_rule

RMF Control

AC-3

Severity

M

CCI

Version

CNTR-K8-000310

Vuln IDs

V-242385

Rule IDs

SV-242385r863961_rule

Limiting the number of attack vectors and implementing authentication and encryption on the endpoints available to external sources is paramount when securing the overall Kubernetes cluster. The Controller Manager API service exposes port 10252/TCP by default for health and metrics information use. This port does not encrypt or authenticate connections. If this port is exposed externally, an attacker can use this port to attack the entire Kubernetes cluster. By setting the bind address to only localhost (i.e., 127.0.0.1), only those internal services that require health and metrics information can access the Control Manager API.

Checks: C-45660r863758_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i bind-address * If the setting bind-address is not set to "127.0.0.1" or is not found in the Kubernetes Controller Manager manifest file, this is a finding.

Fix: F-45618r863759_fix

Edit the Kubernetes Controller Manager manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the argument "--bind-address" to "127.0.0.1".

c

The Kubernetes API server must have the insecure port flag disabled.

AC-3 - High - CCI-000213 - V-242386 - SV-242386r863962_rule

RMF Control

AC-3

Severity

H

CCI

Version

CNTR-K8-000320

Vuln IDs

V-242386

Rule IDs

SV-242386r863962_rule

By default, the API server will listen on two ports. One port is the secure port and the other port is called the "localhost port". This port is also called the "insecure port", port 8080. Any requests to this port bypass authentication and authorization checks. If this port is left open, anyone who gains access to the host on which the Control Plane is running can bypass all authorization and authentication mechanisms put in place, and have full control over the entire cluster. Close the insecure port by setting the API server's --insecure-port flag to "0", ensuring that the --insecure-bind-address is not set.

Checks: C-45661r863761_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i insecure-port * If the setting insecure-port is not set to "0" or is not configured in the Kubernetes API server manifest file, this is a finding. NOTE: --insecure-port flag has been deprecated and can only be set to 0, **This flag will be removed in v1.24.*

Fix: F-45619r863762_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the argument --insecure-port to "0".

c

The Kubernetes Kubelet must have the read-only port flag disabled.

AC-3 - High - CCI-000213 - V-242387 - SV-242387r863963_rule

RMF Control

AC-3

Severity

H

CCI

Version

CNTR-K8-000330

Vuln IDs

V-242387

Rule IDs

SV-242387r863963_rule

Kubelet serves a small REST API with read access to port 10255. The read-only port for Kubernetes provides no authentication or authorization security control. Providing unrestricted access on port 10255 exposes Kubernetes pods and containers to malicious attacks or compromise. Port 10255 is deprecated and should be disabled. Close the read-only-port by setting the API server's read-only port flag to "0".

Checks: C-45662r863764_chk

Run the following command on each Worker Node: ps -ef | grep kubelet Verify that the --read-only-port argument exists and is set to "0". If the --read-only-port argument exists and is not set to "0", this is a finding. If the --read-only-port argument does not exist, check the Control Plane Kubelet config file: On the Kubernetes Control Plane, run the command: ps -ef | grep kubelet Check the config file (path identified by: --config). Verify there is a readOnlyPort entry in the config file and it is set to "0". If the readOnlyPort argument exists and is not set to "0" this is a finding. If "--read-only-port=0" argument does not exist on the worker nodes and "readOnlyPort=0" does not exist on the Control Plane, this is a finding.

Fix: F-45620r863765_fix

Edit the Kubernetes Kubelet file in the --config directory on the Kubernetes Control Plane: Set "readOnlyPort=0" If using worker node arguments, edit the kubelet service file (identified in the --config directory): On each Worker Node: set the parameter in KUBELET_SYSTEM_PODS_ARGS variable to "--read-only-port=0". Reset Kubelet service using the following command: service kubelet restart

c

The Kubernetes API server must have the insecure bind address not set.

AC-3 - High - CCI-000213 - V-242388 - SV-242388r863964_rule

RMF Control

AC-3

Severity

H

CCI

Version

CNTR-K8-000340

Vuln IDs

V-242388

Rule IDs

SV-242388r863964_rule

By default, the API server will listen on two ports and addresses. One address is the secure address and the other address is called the "insecure bind" address and is set by default to localhost. Any requests to this address bypass authentication and authorization checks. If this insecure bind address is set to localhost, anyone who gains access to the host on which the Control Plane is running can bypass all authorization and authentication mechanisms put in place and have full control over the entire cluster. Close or set the insecure bind address by setting the API server's --insecure-bind-address flag to an IP or leave it unset and ensure that the --insecure-bind-port is not set.

Checks: C-45663r863767_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i insecure-bind-address * If the setting insecure-bind-address is found and set to "localhost" in the Kubernetes API manifest file, this is a finding.

Fix: F-45621r863768_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Remove the value for the --insecure-bind-address setting.

b

The Kubernetes API server must have the secure port set.

AC-3 - Medium - CCI-000213 - V-242389 - SV-242389r863965_rule

RMF Control

AC-3

Severity

M

CCI

Version

CNTR-K8-000350

Vuln IDs

V-242389

Rule IDs

SV-242389r863965_rule

By default, the API server will listen on what is rightfully called the secure port, port 6443. Any requests to this port will perform authentication and authorization checks. If this port is disabled, anyone who gains access to the host on which the Control Plane is running has full control of the entire cluster over encrypted traffic. Open the secure port by setting the API server's --secure-port flag to a value other than "0".

Checks: C-45664r863770_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i secure-port * If the setting secure-port is set to "0" or is not configured in the Kubernetes API manifest file, this is a finding.

Fix: F-45622r863771_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the argument --secure-port to a value greater than "0".

c

The Kubernetes API server must have anonymous authentication disabled.

AC-3 - High - CCI-000213 - V-242390 - SV-242390r863966_rule

RMF Control

AC-3

Severity

H

CCI

Version

CNTR-K8-000360

Vuln IDs

V-242390

Rule IDs

SV-242390r863966_rule

The Kubernetes API Server controls Kubernetes via an API interface. A user who has access to the API essentially has root access to the entire Kubernetes cluster. To control access, users must be authenticated and authorized. By allowing anonymous connections, the controls put in place to secure the API can be bypassed. Setting anonymous authentication to "false" also disables unauthenticated requests from kubelets. While there are instances where anonymous connections may be needed (e.g., health checks) and Role-Based Access Controls (RBAC) are in place to limit the anonymous access, this access should be disabled, and only enabled when necessary.

Checks: C-45665r863773_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i anonymous-auth * If the setting anonymous-auth is set to "true" in the Kubernetes API Server manifest file, this is a finding.

Fix: F-45623r863774_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the argument --anonymous-auth to "false".

c

The Kubernetes Kubelet must have anonymous authentication disabled.

AC-3 - High - CCI-000213 - V-242391 - SV-242391r863967_rule

RMF Control

AC-3

Severity

H

CCI

Version

CNTR-K8-000370

Vuln IDs

V-242391

Rule IDs

SV-242391r863967_rule

A user who has access to the Kubelet essentially has root access to the nodes contained within the Kubernetes Control Plane. To control access, users must be authenticated and authorized. By allowing anonymous connections, the controls put in place to secure the Kubelet can be bypassed. Setting anonymous authentication to "false" also disables unauthenticated requests from kubelets. While there are instances where anonymous connections may be needed (e.g., health checks) and Role-Based Access Controls (RBAC) are in place to limit the anonymous access, this access must be disabled and only enabled when necessary.

Checks: C-45666r863776_chk

Run the following command on each Worker Node: ps -ef | grep kubelet Verify that the --anonymous-auth argument exists and is set to "false". If the --anonymous-auth argument exists and is not set to "false", this is a finding. If the --anonymous-auth argument does not exist, check the Control Plane Kubelet config file: On the Kubernetes Control Plane, run the command: ps -ef | grep kubelet Check the config file (path identified by: --config). Verify "authentication: anonymous: enabled=false". If this is not set to "false", this is a finding. If "--anonymous-auth=false" argument does not exist on the worker nodes or "authentication: anonymous: enabled=false" does not exist on the Control Plane, this is a finding.

Fix: F-45624r863777_fix

Edit the Kubernetes Kubelet file in the --config directory on the Kubernetes Control Plane: Set "authentication: anonymous: enabled=false" If using worker node arguments, edit the kubelet service file (identified in the --config directory): On each Worker Node: set the parameter in KUBELET_SYSTEM_PODS_ARGS variable to "--anonymous-auth=false". Reset Kubelet service using the following command: service kubelet restart

c

The Kubernetes kubelet must enable explicit authorization.

AC-3 - High - CCI-000213 - V-242392 - SV-242392r863968_rule

RMF Control

AC-3

Severity

H

CCI

Version

CNTR-K8-000380

Vuln IDs

V-242392

Rule IDs

SV-242392r863968_rule

Kubelet is the primary agent on each node. The API server communicates with each kubelet to perform tasks such as starting/stopping pods. By default, kubelets allow all authenticated requests, even anonymous ones, without requiring any authorization checks from the API server. This default behavior bypasses any authorization controls put in place to limit what users may perform within the Kubernetes cluster. To change this behavior, the default setting of AlwaysAllow for the authorization mode must be set to "Webhook".

Checks: C-45667r863779_chk

Run the following command on each Worker Node: ps -ef | grep kubelet Verify that the --authorization-mode exists and is set to "Webhook". If the --authorization-mode argument exists and is not set to "Webhook", this is a finding. If the --authorization-mode does not exist, check the Control Plane Kubelet config file: On the Kubernetes Control Plane, run the command: ps -ef | grep kubelet Check the config file (path identified by: --config). Verify authorization: mode. If this is not set to "Webhook", this is a finding. If "--authorization-mode=Webhook" argument does not exist on the worker nodes or "authorization: mode=Webhook" does not exist on the Control Plane, this is a finding.

Fix: F-45625r863780_fix

Edit the Kubernetes Kubelet file in the --config directory on the Kubernetes Control Plane: Set the argument "authorization: mode=Webhook" If using worker node arguments, edit the kubelet service file identified in the --config directory: On each Worker Node: set the parameter in KUBELET_SYSTEM_PODS_ARGS variable to "--authorization-mode=Webhook". Reset Kubelet service using the following command: service kubelet restart

b

Kubernetes Worker Nodes must not have sshd service running.

AC-3 - Medium - CCI-000213 - V-242393 - SV-242393r863969_rule

RMF Control

AC-3

Severity

M

CCI

Version

CNTR-K8-000400

Vuln IDs

V-242393

Rule IDs

SV-242393r863969_rule

Worker Nodes are maintained and monitored by the Control Plane. Direct access and manipulation of the nodes should not take place by administrators. Worker nodes should be treated as immutable and updated via replacement rather than in-place upgrades.

Checks: C-45668r712533_chk

Log in to each worker node. Verify that the sshd service is not running. To validate that the service is not running, run the command: systemctl status sshd If the service sshd is active (running), this is a finding. Note: If console access is not available, SSH access can be attempted. If the worker nodes cannot be reached, this requirement is "not a finding".

Fix: F-45626r863782_fix

To stop the sshd service, run the command: systemctl stop sshd Note: If access to the worker node is through an SSH session, it is important to realize there are two requirements for disabling and stopping the sshd service and they should be done during the same SSH session. Disabling the service must be performed first and then the service stopped to guarantee both settings can be made if the session is interrupted.

b

Kubernetes Worker Nodes must not have the sshd service enabled.

AC-3 - Medium - CCI-000213 - V-242394 - SV-242394r863970_rule

RMF Control

AC-3

Severity

M

CCI

Version

CNTR-K8-000410

Vuln IDs

V-242394

Rule IDs

SV-242394r863970_rule

Worker Nodes are maintained and monitored by the Control Plane. Direct access and manipulation of the nodes must not take place by administrators. Worker nodes must be treated as immutable and updated via replacement rather than in-place upgrades.

Checks: C-45669r712536_chk

Log in to each worker node. Verify that the sshd service is not enabled. To validate the service is not enabled, run the command: systemctl is-enabled sshd.service If the service sshd is enabled, this is a finding. Note: If console access is not available, SSH access can be attempted. If the worker nodes cannot be reached, this requirement is "not a finding".

Fix: F-45627r863784_fix

To disable the sshd service, run the command: chkconfig sshd off Note: If access to the worker node is through an SSH session, it is important to realize there are two requirements for disabling and stopping the sshd service that must be done during the same SSH session. Disabling the service must be performed first and then the service stopped to guarantee both settings can be made if the session is interrupted.

b

Kubernetes dashboard must not be enabled.

AC-3 - Medium - CCI-000213 - V-242395 - SV-242395r863971_rule

RMF Control

AC-3

Severity

M

CCI

Version

CNTR-K8-000420

Vuln IDs

V-242395

Rule IDs

SV-242395r863971_rule

While the Kubernetes dashboard is not inherently insecure on its own, it is often coupled with a misconfiguration of Role-Based Access control (RBAC) permissions that can unintentionally over-grant access. It is not commonly protected with "NetworkPolicies", preventing all pods from being able to reach it. In increasingly rare circumstances, the Kubernetes dashboard is exposed publicly to the internet.

Checks: C-45670r863786_chk

From the Control Plane, run the command: kubectl get pods --all-namespaces -l k8s-app=kubernetes-dashboard If any resources are returned, this is a finding.

Fix: F-45628r712540_fix

Delete the Kubernetes dashboard deployment with the following command: kubectl delete deployment kubernetes-dashboard --namespace=kube-system

b

Kubernetes Kubectl cp command must give expected access and results.

AC-3 - Medium - CCI-000213 - V-242396 - SV-242396r863972_rule

RMF Control

AC-3

Severity

M

CCI

Version

CNTR-K8-000430

Vuln IDs

V-242396

Rule IDs

SV-242396r863972_rule

One of the tools heavily used to interact with containers in the Kubernetes cluster is kubectl. The command is the tool System Administrators used to create, modify, and delete resources. One of the capabilities of the tool is to copy files to and from running containers (i.e., kubectl cp). The command uses the "tar" command of the container to copy files from the container to the host executing the "kubectl cp" command. If the "tar" command on the container has been replaced by a malicious user, the command can copy files anywhere on the host machine. This flaw has been fixed in later versions of the tool. It is recommended to use kubectl versions newer than 1.12.9.

Checks: C-45671r863788_chk

From the Control Plane and each Worker node, check the version of kubectl by executing the command: kubectl version --client If the Control Plane or any Worker nodes are not using kubectl version 1.12.9 or newer, this is a finding.

Fix: F-45629r863789_fix

Upgrade the Control Plane and Worker nodes to the latest version of kubectl.

c

The Kubernetes kubelet static PodPath must not enable static pods.

AC-3 - High - CCI-000213 - V-242397 - SV-242397r863973_rule

RMF Control

AC-3

Severity

H

CCI

Version

CNTR-K8-000440

Vuln IDs

V-242397

Rule IDs

SV-242397r863973_rule

Allowing kubelet to set a staticPodPath gives containers with root access permissions to traverse the hosting filesystem. The danger comes when the container can create a manifest file within the /etc/kubernetes/manifests directory. When a manifest is created within this directory, containers are entirely governed by the Kubelet not the API Server. The container is not susceptible to admission control at all. Any containers or pods that are instantiated in this manner are called "static pods" and are meant to be used for pods such as the API server, scheduler, controller, etc., not workload pods that need to be governed by the API Server.

Checks: C-45672r863791_chk

On the Kubernetes Control Plane and Worker nodes, run the command: ps -ef | grep kubelet Check the config file (path identified by: --config): Change to the directory identified by --config (example /etc/sysconfig/) run the command: grep -i staticPodPath kubelet If any of the nodes return a value for staticPodPath, this is a finding.

Fix: F-45630r863792_fix

Edit the kubelet file on each node under the --config directory and remove the staticPodPath setting. Reset Kubelet service using the following command: service kubelet restart

b

Kubernetes DynamicAuditing must not be enabled.

AC-3 - Medium - CCI-000213 - V-242398 - SV-242398r863974_rule

RMF Control

AC-3

Severity

M

CCI

Version

CNTR-K8-000450

Vuln IDs

V-242398

Rule IDs

SV-242398r863974_rule

Protecting the audit data from change or deletion is important when an attack occurs. One way an attacker can cover their tracks is to change or delete audit records. This will either make the attack unnoticeable or make it more difficult to investigate how the attack took place and what changes were made. The audit data can be protected through audit log file protections and user authorization. One way for an attacker to thwart these measures is to send the audit logs to another source and filter the audited results before sending them on to the original target. This can be done in Kubernetes through the configuration of dynamic audit webhooks through the DynamicAuditing flag.

Checks: C-45673r863794_chk

On the Control Plane, change to the manifests' directory at /etc/kubernetes/manifests and run the command: grep -i feature-gates * Review the feature-gates setting, if one is returned. If the feature-gates setting is available and contains the DynamicAuditing flag set to "true", this is a finding. Change to the directory /etc/sysconfig on the Control Plane and each Worker Node and execute the command: grep -i feature-gates kubelet Review every feature-gates setting that is returned. If any feature-gates setting is available and contains the "DynamicAuditing" flag set to "true", this is a finding.

Fix: F-45631r717018_fix

Edit any manifest files or kubelet config files that contain the feature-gates setting with DynamicAuditing set to "true". Set the flag to "false" or remove the "DynamicAuditing" setting completely. Restart the kubelet service if the kubelet config file if the kubelet config file is changed.

b

Kubernetes DynamicKubeletConfig must not be enabled.

AC-3 - Medium - CCI-000213 - V-242399 - SV-242399r863975_rule

RMF Control

AC-3

Severity

M

CCI

Version

CNTR-K8-000460

Vuln IDs

V-242399

Rule IDs

SV-242399r863975_rule

Kubernetes allows a user to configure kubelets with dynamic configurations. When dynamic configuration is used, the kubelet will watch for changes to the configuration file. When changes are made, the kubelet will automatically restart. Allowing this capability bypasses access restrictions and authorizations. Using this capability, an attacker can lower the security posture of the kubelet, which includes allowing the ability to run arbitrary commands in any container running on that node.

Checks: C-45674r863796_chk

On the Control Plane, change to the manifests' directory at /etc/kubernetes/manifests and run the command: grep -i feature-gates * Review the feature-gates setting if one is returned. If the feature-gates setting does not exist or feature-gates does not contain the DynamicKubeletConfig flag or the "DynamicKubletConfig" flag is set to "true", this is a finding. Change to the directory /etc/sysconfig on the Control Plane and each Worker node and execute the command: grep -i feature-gates kubelet Review every feature-gates setting if one is returned. If the feature-gates setting does not exist or feature-gates does not contain the DynamicKubeletConfig flag or the DynamicKubletConfig flag is set to "true", this is a finding.

Fix: F-45632r863797_fix

Edit any manifest file or kubelet config file that does not contain a feature-gates setting or has DynamicKubeletConfig set to "true". An omission of DynamicKubeletConfig within the feature-gates defaults to true. Set DynamicKubeletConfig to "false". Restart the kubelet service if the kubelet config file is changed.

b

The Kubernetes API server must have Alpha APIs disabled.

AC-3 - Medium - CCI-000213 - V-242400 - SV-242400r863976_rule

RMF Control

AC-3

Severity

M

CCI

Version

CNTR-K8-000470

Vuln IDs

V-242400

Rule IDs

SV-242400r863976_rule

Kubernetes allows alpha API calls within the API server. The alpha features are disabled by default since they are not ready for production and likely to change without notice. These features may also contain security issues that are rectified as the feature matures. To keep the Kubernetes cluster secure and stable, these alpha features must not be used.

Checks: C-45675r863799_chk

On the Control Plane, change to the manifests' directory at /etc/kubernetes/manifests and run the command: grep -i feature-gates * Review the feature-gates setting, if one is returned. If the feature-gates setting is available and contains the AllAlpha flag set to "true", this is a finding.

Fix: F-45633r712555_fix

Edit any manifest files that contain the feature-gates setting with AllAlpha set to "true". Set the flag to "false" or remove the AllAlpha setting completely. (AllAlpha- default=false)

b

The Kubernetes API Server must have an audit policy set.

AU-14 - Medium - CCI-001464 - V-242401 - SV-242401r863977_rule

RMF Control

AU-14

Severity

M

CCI

CCI-001464

Version

CNTR-K8-000600

Vuln IDs

V-242401

Rule IDs

SV-242401r863977_rule

When Kubernetes is started, components and user services are started. For auditing startup events, and events for components and services, it is important that auditing begin on startup. Within Kubernetes, audit data for all components is generated by the API server. To enable auditing to begin, an audit policy must be defined for the events and the information to be stored with each event. It is also necessary to give a secure location where the audit logs are to be stored. If an audit log path is not specified, all audit data is sent to studio.

Checks: C-45676r863801_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i audit-policy-file * If the audit-policy-file is not set, this is a finding.

Fix: F-45634r863802_fix

Edit the Kubernetes API Server manifest and set "--audit-policy-file" to the audit policy file. Note: If the API server is running as a Pod, then the manifest will also need to be updated to mount the host system filesystem where the audit policy file resides.

b

The Kubernetes API Server must have an audit log path set.

AU-14 - Medium - CCI-001464 - V-242402 - SV-242402r863978_rule

RMF Control

AU-14

Severity

M

CCI

CCI-001464

Version

CNTR-K8-000610

Vuln IDs

V-242402

Rule IDs

SV-242402r863978_rule

When Kubernetes is started, components and user services are started for auditing startup events, and events for components and services, it is important that auditing begin on startup. Within Kubernetes, audit data for all components is generated by the API server. To enable auditing to begin, an audit policy must be defined for the events and the information to be stored with each event. It is also necessary to give a secure location where the audit logs are to be stored. If an audit log path is not specified, all audit data is sent to studio.

Checks: C-45677r863804_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i audit-log-path * If the audit-log-path is not set, this is a finding.

Fix: F-45635r863805_fix

Edit the Kubernetes API Server manifest and set "--audit-log-path" to a secure location for the audit logs to be written. Note: If the API server is running as a Pod, then the manifest will also need to be updated to mount the host system filesystem where the audit log file is to be written.

b

Kubernetes API Server must generate audit records that identify what type of event has occurred, identify the source of the event, contain the event results, identify any users, and identify any containers associated with the event.

AC-2 - Medium - CCI-000018 - V-242403 - SV-242403r863979_rule

RMF Control

AC-2

Severity

M

CCI

CCI-000018

Version

CNTR-K8-000700

Vuln IDs

V-242403

Rule IDs

SV-242403r863979_rule

Within Kubernetes, audit data for all components is generated by the API server. This audit data is important when there are issues, to include security incidents that must be investigated. To make the audit data worthwhile for the investigation of events, it is necessary to have the appropriate and required data logged. To fully understand the event, it is important to identify any users associated with the event. The API server policy file allows for the following levels of auditing: None - Do not log events that match the rule. Metadata - Log request metadata (requesting user, timestamp, resource, verb, etc.) but not request or response body. Request - Log event metadata and request body but not response body. RequestResponse - Log event metadata, request, and response bodies. Satisfies: SRG-APP-000026-CTR-000070, SRG-APP-000027-CTR-000075, SRG-APP-000028-CTR-000080, SRG-APP-000101-CTR-000205, SRG-APP-000100-CTR-000200, SRG-APP-000100-CTR-000195, SRG-APP-000099-CTR-000190, SRG-APP-000098-CTR-000185, SRG-APP-000095-CTR-000170, SRG-APP-000096-CTR-000175, SRG-APP-000097-CTR-000180, SRG-APP-000507-CTR-001295, SRG-APP-000504-CTR-001280, SRG-APP-000503-CTR-001275, SRG-APP-000501-CTR-001265, SRG-APP-000500-CTR-001260, SRG-APP-000497-CTR-001245, SRG-APP-000496-CTR-001240, SRG-APP-000493-CTR-001225, SRG-APP-000492-CTR-001220, SRG-APP-000343-CTR-000780, SRG-APP-000381-CTR-000905

Checks: C-45678r863807_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i audit-policy-file If the audit-policy-file is not set, this is a finding. The file given is the policy file and defines what is audited and what information is included with each event. The policy file must look like this: # Log all requests at the RequestResponse level. apiVersion: audit.k8s.io/vX (Where X is the latest apiVersion) kind: Policy rules: - level: RequestResponse If the audit policy file does not look like above, this is a finding.

Fix: F-45636r712564_fix

Edit the Kubernetes API Server audit policy and set it to look like the following: # Log all requests at the RequestResponse level. apiVersion: audit.k8s.io/vX (Where X is the latest apiVersion) kind: Policy rules: - level: RequestResponse

b

Kubernetes Kubelet must deny hostname override.

CM-5 - Medium - CCI-001499 - V-242404 - SV-242404r863980_rule

RMF Control

CM-5

Severity

M

CCI

Version

CNTR-K8-000850

Vuln IDs

V-242404

Rule IDs

SV-242404r863980_rule

Kubernetes allows for the overriding of hostnames. Allowing this feature to be implemented within the kubelets may break the TLS setup between the kubelet service and the API server. This setting also can make it difficult to associate logs with nodes if security analytics needs to take place. The better practice is to setup nodes with resolvable FQDNs and avoid overriding the hostnames.

Checks: C-45679r863809_chk

On the Kubernetes Control Plane and Worker nodes, run the command: ps -ef | grep kubelet Check the config file (path identified by: --config): Change to the directory identified by --config (example /etc/sysconfig/) run the command: grep -i hostname-override kubelet If any of the nodes have the setting "hostname-override" present, this is a finding.

Fix: F-45637r863810_fix

Edit the kubelet file on each node under the --config directory and remove the hostname-override setting. Reset Kubelet service using the following command: service kubelet restart

b

The Kubernetes manifests must be owned by root.

CM-5 - Medium - CCI-001499 - V-242405 - SV-242405r863981_rule

RMF Control

CM-5

Severity

M

CCI

Version

CNTR-K8-000860

Vuln IDs

V-242405

Rule IDs

SV-242405r863981_rule

The manifest files contain the runtime configuration of the API server, proxy, scheduler, controller, and etcd. If an attacker can gain access to these files, changes can be made to open vulnerabilities and bypass user authorizations inherit within Kubernetes with RBAC implemented.

Checks: C-45680r863812_chk

On the Control Plane, change to the /etc/kubernetes/manifest directory. Run the command: ls -l * Each manifest file must be owned by root:root. If any manifest file is not owned by root:root, this is a finding.

Fix: F-45638r863813_fix

On the Control Plane, change to the /etc/kubernetes/manifest directory. Run the command: chown root:root * To verify the change took place, run the command: ls -l * All the manifest files should be owned by root:root.

b

The Kubernetes kubelet configuration file must be owned by root.

CM-5 - Medium - CCI-001499 - V-242406 - SV-242406r863982_rule

RMF Control

CM-5

Severity

M

CCI

Version

CNTR-K8-000880

Vuln IDs

V-242406

Rule IDs

SV-242406r863982_rule

The kubelet configuration file contains the runtime configuration of the kubelet service. If an attacker can gain access to this file, changes can be made to open vulnerabilities and bypass user authorizations inherent within Kubernetes with RBAC implemented.

Checks: C-45681r863815_chk

On the Kubernetes Control Plane and Worker nodes, run the command: ps -ef | grep kubelet Check the config file (path identified by: --config): Change to the directory identified by --config (example /etc/sysconfig/) run the command: ls -l kubelet Each kubelet configuration file must be owned by root:root. If any manifest file is not owned by root:root, this is a finding.

Fix: F-45639r863816_fix

On the Control Plane and Worker nodes, change to the --config directory. Run the command: chown root:root kubelet To verify the change took place, run the command: ls -l kubelet The kubelet file should now be owned by root:root.

b

The Kubernetes kubelet configuration files must have file permissions set to 644 or more restrictive.

CM-5 - Medium - CCI-001499 - V-242407 - SV-242407r863983_rule

RMF Control

CM-5

Severity

M

CCI

Version

CNTR-K8-000890

Vuln IDs

V-242407

Rule IDs

SV-242407r863983_rule

The kubelet configuration file contains the runtime configuration of the kubelet service. If an attacker can gain access to this file, changes can be made to open vulnerabilities and bypass user authorizations inherit within Kubernetes with RBAC implemented.

Checks: C-45682r863818_chk

On the Control Plane and worker nodes, change to the /etc/kubernetes/manifest directory. Run the command: ls -l kubelet Each kubelet configuration file must have permissions of "644" or more restrictive. If any kubelet configuration file is less restrictive than "644", this is a finding.

Fix: F-45640r863819_fix

On the Control Plane, change to the /etc/kubernetes/manifest directory. Run the command: chmod 644 kubelet To verify the change took place, run the command: ls -l kubelet The kubelet file should now have the permissions of "644".

b

The Kubernetes manifests must have least privileges.

CM-5 - Medium - CCI-001499 - V-242408 - SV-242408r863984_rule

RMF Control

CM-5

Severity

M

CCI

Version

CNTR-K8-000900

Vuln IDs

V-242408

Rule IDs

SV-242408r863984_rule

The manifest files contain the runtime configuration of the API server, scheduler, controller, and etcd. If an attacker can gain access to these files, changes can be made to open vulnerabilities and bypass user authorizations inherent within Kubernetes with RBAC implemented. Satisfies: SRG-APP-000133-CTR-000310, SRG-APP-000133-CTR-000295

Checks: C-45683r863821_chk

On the Control Plane, change to the /etc/kubernetes/manifest directory. Run the command: ls -l * Each manifest file must have permissions "644" or more restrictive. If any manifest file is less restrictive than "644", this is a finding.

Fix: F-45641r863822_fix

On the Control Plane, change to the /etc/kubernetes/manifest directory. Run the command: chmod 644 * To verify the change took place, run the command: ls -l * All the manifest files should now have privileges of "644".

b

Kubernetes Controller Manager must disable profiling.

CM-7 - Medium - CCI-000381 - V-242409 - SV-242409r863985_rule

RMF Control

CM-7

Severity

M

CCI

CCI-000381

Version

CNTR-K8-000910

Vuln IDs

V-242409

Rule IDs

SV-242409r863985_rule

Kubernetes profiling provides the ability to analyze and troubleshoot Controller Manager events over a web interface on a host port. Enabling this service can expose details about the Kubernetes architecture. This service must not be enabled unless deemed necessary.

Checks: C-45684r863824_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i profiling * If the setting "profiling" is not configured in the Kubernetes Controller Manager manifest file or it is set to "True", this is a finding.

Fix: F-45642r863825_fix

Edit the Kubernetes Controller Manager manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the argument "--profiling value" to "false".

b

The Kubernetes API Server must enforce ports, protocols, and services (PPS) that adhere to the Ports, Protocols, and Services Management Category Assurance List (PPSM CAL).

CM-7 - Medium - CCI-000382 - V-242410 - SV-242410r863986_rule

RMF Control

CM-7

Severity

M

CCI

Version

CNTR-K8-000920

Vuln IDs

V-242410

Rule IDs

SV-242410r863986_rule

Kubernetes API Server PPSs must be controlled and conform to the PPSM CAL. Those PPS that fall outside the PPSM CAL must be blocked. Instructions on the PPSM can be found in DoD Instruction 8551.01 Policy.

Checks: C-45685r863827_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep kube-apiserver.manifest -I -secure-port * grep kube-apiserver.manifest -I -etcd-servers * -edit manifest file: VIM <Manifest Name> Review livenessProbe: HttpGet: Port: Review ports: - containerPort: hostPort: - containerPort: hostPort: Run Command: kubectl describe services –all-namespace Search labels for any apiserver names spaces. Port: Any manifest and namespace PPS or services configuration not in compliance with PPSM CAL is a finding. Review the information systems documentation and interview the team, gain an understanding of the API Server architecture, and determine applicable PPS. If there are any ports, protocols, and services in the system documentation not in compliance with the CAL PPSM, this is a finding. Any PPS not set in the system documentation is a finding. Review findings against the most recent PPSM CAL: https://cyber.mil/ppsm/cal/ Verify API Server network boundary with the PPS associated with the CAL Assurance Categories. Any PPS not in compliance with the CAL Assurance Category requirements is a finding.

Fix: F-45643r712585_fix

Amend any system documentation requiring revision. Update Kubernetes API Server manifest and namespace PPS configuration to comply with PPSM CAL.

b

The Kubernetes Scheduler must enforce ports, protocols, and services (PPS) that adhere to the Ports, Protocols, and Services Management Category Assurance List (PPSM CAL).

CM-7 - Medium - CCI-000382 - V-242411 - SV-242411r863987_rule

RMF Control

CM-7

Severity

M

CCI

Version

CNTR-K8-000930

Vuln IDs

V-242411

Rule IDs

SV-242411r863987_rule

Kubernetes Scheduler PPS must be controlled and conform to the PPSM CAL. Those ports, protocols, and services that fall outside the PPSM CAL must be blocked. Instructions on the PPSM can be found in DoD Instruction 8551.01 Policy.

Checks: C-45686r863829_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep kube-scheduler.manifest -I -insecure-port grep kube-scheduler.manifest -I -secure-port -edit manifest file: VIM <Manifest Name> Review livenessProbe: HttpGet: Port: Review ports: - containerPort: hostPort: - containerPort: hostPort: Run Command: kubectl describe services –all-namespace Search labels for any scheduler names spaces. Port: Any manifest and namespace PPS configuration not in compliance with PPSM CAL is a finding. Review the information systems documentation and interview the team, gain an understanding of the Scheduler architecture, and determine applicable PPS. Any PPS in the system documentation not in compliance with the CAL PPSM is a finding. Any PPSs not set in the system documentation is a finding. Review findings against the most recent PPSM CAL: https://cyber.mil/ppsm/cal/ Verify Scheduler network boundary with the PPS associated with the CAL Assurance Categories. Any PPS not in compliance with the CAL Assurance Category requirements is a finding.

Fix: F-45644r712588_fix

Amend any system documentation requiring revision. Update Kubernetes Scheduler manifest and namespace PPS configuration to comply with the PPSM CAL.

b

The Kubernetes Controllers must enforce ports, protocols, and services (PPS) that adhere to the Ports, Protocols, and Services Management Category Assurance List (PPSM CAL).

CM-7 - Medium - CCI-000382 - V-242412 - SV-242412r863988_rule

RMF Control

CM-7

Severity

M

CCI

Version

CNTR-K8-000940

Vuln IDs

V-242412

Rule IDs

SV-242412r863988_rule

Kubernetes Controller ports, protocols, and services must be controlled and conform to the PPSM CAL. Those PPS that fall outside the PPSM CAL must be blocked. Instructions on the PPSM can be found in DoD Instruction 8551.01 Policy.

Checks: C-45687r863831_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep kube-scheduler.manifest -I -secure-port -edit manifest file: VIM <Manifest Name: Review livenessProbe: HttpGet: Port: Review ports: - containerPort: hostPort: - containerPort: hostPort: Run Command: kubectl describe services –all-namespace Search labels for any controller names spaces. Any manifest and namespace PPS or services configuration not in compliance with PPSM CAL is a finding. Review the information systems documentation and interview the team, gain an understanding of the Controller architecture, and determine applicable PPS. Any PPS in the system documentation not in compliance with the CAL PPSM is a finding. Any PPS not set in the system documentation is a finding. Review findings against the most recent PPSM CAL: https://cyber.mil/ppsm/cal/ Verify Controller network boundary with the PPS associated with the Controller for Assurance Categories. Any PPS not in compliance with the CAL Assurance Category requirements is a finding.

Fix: F-45645r712591_fix

Amend any system documentation requiring revision. Update Kubernetes Controller manifest and namespace PPS configuration to comply with PPSM CAL.

b

The Kubernetes etcd must enforce ports, protocols, and services (PPS) that adhere to the Ports, Protocols, and Services Management Category Assurance List (PPSM CAL).

CM-7 - Medium - CCI-000382 - V-242413 - SV-242413r863989_rule

RMF Control

CM-7

Severity

M

CCI

Version

CNTR-K8-000950

Vuln IDs

V-242413

Rule IDs

SV-242413r863989_rule

Kubernetes etcd PPS must be controlled and conform to the PPSM CAL. Those PPS that fall outside the PPSM CAL must be blocked. Instructions on the PPSM can be found in DoD Instruction 8551.01 Policy.

Checks: C-45688r863833_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep kube-apiserver.manifest -I -etcd-servers * -edit etcd-main.manifest file: VIM <Manifest Name: Review livenessProbe: HttpGet: Port: Review ports: - containerPort: hostPort: - containerPort: hostPort: Run Command: kubectl describe services –all-namespace Search labels for any apiserver names spaces. Port: Any manifest and namespace PPS configuration not in compliance with PPSM CAL is a finding. Review the information systems documentation and interview the team, gain an understanding of the etcd architecture, and determine applicable PPS. Any PPS in the system documentation not in compliance with the CAL PPSM is a finding. Any PPS not set in the system documentation is a finding. Review findings against the most recent PPSM CAL: https://cyber.mil/ppsm/cal/ Verify etcd network boundary with the PPS associated with the CAL Assurance Categories. Any PPS not in compliance with the CAL Assurance Category requirements is a finding.

Fix: F-45646r712594_fix

Amend any system documentation requiring revision. Update Kubernetes etcd manifest and namespace PPS configuration to comply with PPSM CAL.

b

The Kubernetes cluster must use non-privileged host ports for user pods.

CM-7 - Medium - CCI-000382 - V-242414 - SV-242414r863990_rule

RMF Control

CM-7

Severity

M

CCI

Version

CNTR-K8-000960

Vuln IDs

V-242414

Rule IDs

SV-242414r863990_rule

Privileged ports are those ports below 1024 and that require system privileges for their use. If containers can use these ports, the container must be run as a privileged user. Kubernetes must stop containers that try to map to these ports directly. Allowing non-privileged ports to be mapped to the container-privileged port is the allowable method when a certain port is needed. An example is mapping port 8080 externally to port 80 in the container.

Checks: C-45689r863835_chk

On the Control Plane, run the command: kubectl get pods --all-namespaces The list returned is all pods running within the Kubernetes cluster. For those pods running within the user namespaces (System namespaces are kube-system, kube-node-lease and kube-public), run the command: kubectl get pod podname -o yaml | grep -i port Note: In the above command, "podname" is the name of the pod. For the command to work correctly, the current context must be changed to the namespace for the pod. The command to do this is: kubectl config set-context --current --namespace=namespace-name (Note: "namespace-name" is the name of the namespace.) Review the ports that are returned for the pod. If any host-privileged ports are returned for any of the pods, this is a finding.

Fix: F-45647r717032_fix

For any of the pods that are using host-privileged ports, reconfigure the pod to use a service to map a host non-privileged port to the pod port or reconfigure the image to use non-privileged ports.

c

Secrets in Kubernetes must not be stored as environment variables.

IA-5 - High - CCI-000196 - V-242415 - SV-242415r863991_rule

RMF Control

IA-5

Severity

H

CCI

CCI-000196

Version

CNTR-K8-001160

Vuln IDs

V-242415

Rule IDs

SV-242415r863991_rule

Secrets, such as passwords, keys, tokens, and certificates should not be stored as environment variables. These environment variables are accessible inside Kubernetes by the "Get Pod" API call, and by any system, such as CI/CD pipeline, which has access to the definition file of the container. Secrets must be mounted from files or stored within password vaults.

Checks: C-45690r863838_chk

On the Kubernetes Control Plane, run the following command: kubectl get all -o jsonpath='{range .items[?(@..secretKeyRef)]} {.kind} {.metadata.name} {"\n"}{end}' -A If any of the values returned reference environment variables, this is a finding.

Fix: F-45648r712600_fix

Any secrets stored as environment variables must be moved to the secret files with the proper protections and enforcements or placed within a password vault.

b

Kubernetes must separate user functionality.

SC-2 - Medium - CCI-001082 - V-242417 - SV-242417r863992_rule

RMF Control

SC-2

Severity

M

CCI

CCI-001082

Version

CNTR-K8-001360

Vuln IDs

V-242417

Rule IDs

SV-242417r863992_rule

Separating user functionality from management functionality is a requirement for all the components within the Kubernetes Control Plane. Without the separation, users may have access to management functions that can degrade the Kubernetes architecture and the services being offered, and can offer a method to bypass testing and validation of functions before introduced into a production environment.

Checks: C-45692r863840_chk

On the Control Plane, run the command: kubectl get pods --all-namespaces Review the namespaces and pods that are returned. Kubernetes system namespaces are kube-node-lease, kube-public, and kube-system. If any user pods are present in the Kubernetes system namespaces, this is a finding.

Fix: F-45650r712606_fix

Move any user pods that are present in the Kubernetes system namespaces to user specific namespaces.

b

The Kubernetes API server must use approved cipher suites.

SC-23 - Medium - CCI-001184 - V-242418 - SV-242418r863993_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001400

Vuln IDs

V-242418

Rule IDs

SV-242418r863993_rule

The Kubernetes API server communicates to the kubelet service on the nodes to deploy, update, and delete resources. If an attacker were able to get between this communication and modify the request, the Kubernetes cluster could be compromised. Using approved cypher suites for the communication ensures the protection of the transmitted information, confidentiality, and integrity so that the attacker cannot read or alter this communication.

Checks: C-45693r863842_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i tls-cipher-suites * If the setting feature tls-cipher-suites is not set in the Kubernetes API server manifest file or contains no value or does not contain TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384, this is a finding.

Fix: F-45651r863843_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of tls-cipher-suites to: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384

b

Kubernetes API Server must have the SSL Certificate Authority set.

SC-23 - Medium - CCI-001184 - V-242419 - SV-242419r863994_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001410

Vuln IDs

V-242419

Rule IDs

SV-242419r863994_rule

Kubernetes control plane and external communication is managed by API Server. The main implementation of the API Server is to manage hardware resources for pods and containers using horizontal or vertical scaling. Anyone who can access the API Server can effectively control the Kubernetes architecture. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for API Server, the parameter etcd-cafile must be set. This parameter gives the location of the SSL Certificate Authority file used to secure API Server communication.

Checks: C-45694r863845_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i client-ca-file * If the setting feature client-ca-file is not set in the Kubernetes API server manifest file or contains no value, this is a finding.

Fix: F-45652r863846_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of client-ca-file to path containing Approved Organizational Certificate.

b

Kubernetes Kubelet must have the SSL Certificate Authority set.

SC-23 - Medium - CCI-001184 - V-242420 - SV-242420r863995_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001420

Vuln IDs

V-242420

Rule IDs

SV-242420r863995_rule

Kubernetes container and pod configuration are maintained by Kubelet. Kubelet agents register nodes with the API Server, mount volume storage, and perform health checks for containers and pods. Anyone who gains access to Kubelet agents can effectively control applications within the pods and containers. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for Kubelet, the client-ca-file must be set. This parameter gives the location of the SSL Certificate Authority file used to secure Kubelet communication.

Checks: C-45695r863848_chk

On the Kubernetes Control Plane, run the command: ps -ef | grep kubelet Check the config file (path identified by: --config): Change to the directory identified by --config (example /etc/sysconfig/) run the command: grep -i client-ca-file kubelet If the setting client-ca-file is not set in the Kubernetes API server manifest file or contains no value, this is a finding.

Fix: F-45653r863849_fix

Edit the Kubernetes Kubelet file in the --config directory on the Kubernetes Control Plane: Set the value of client-ca-file to path containing Approved Organizational Certificate. Reset Kubelet service using the following command: service kubelet restart

b

Kubernetes Controller Manager must have the SSL Certificate Authority set.

SC-23 - Medium - CCI-001184 - V-242421 - SV-242421r863996_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001430

Vuln IDs

V-242421

Rule IDs

SV-242421r863996_rule

The Kubernetes Controller Manager is responsible for creating service accounts and tokens for the API Server, maintaining the correct number of pods for every replication controller and provides notifications when nodes are offline. Anyone who gains access to the Controller Manager can generate backdoor accounts, take possession of, or diminish system performance without detection by disabling system notification. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes Controller Manager with a means to be able to authenticate sessions and encrypt traffic.

Checks: C-45696r863851_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i root-ca-file * If the setting client-ca-file is not set in the Kubernetes Controller Manager manifest file or contains no value, this is a finding.

Fix: F-45654r863852_fix

Edit the Kubernetes Controller Manager manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of root-ca-file to path containing Approved Organizational Certificate.

b

Kubernetes API Server must have a certificate for communication.

SC-23 - Medium - CCI-001184 - V-242422 - SV-242422r863997_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001440

Vuln IDs

V-242422

Rule IDs

SV-242422r863997_rule

Kubernetes control plane and external communication is managed by API Server. The main implementation of the API Server is to manage hardware resources for pods and container using horizontal or vertical scaling. Anyone who can access the API Server can effectively control the Kubernetes architecture. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for API Server, the parameter etcd-cafile must be set. This parameter gives the location of the SSL Certificate Authority file used to secure API Server communication.

Checks: C-45697r863854_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i tls-cert-file * grep -i tls-private-key-file * If the setting tls-cert-file and private-key-file is not set in the Kubernetes API server manifest file or contains no value, this is a finding.

Fix: F-45655r863855_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of tls-cert-file and tls-private-key-file to path containing Approved Organizational Certificate.

b

Kubernetes etcd must enable client authentication to secure service.

SC-23 - Medium - CCI-001184 - V-242423 - SV-242423r863998_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001450

Vuln IDs

V-242423

Rule IDs

SV-242423r863998_rule

Kubernetes container and pod configuration are maintained by Kubelet. Kubelet agents register nodes with the API Server, mount volume storage, and perform health checks for containers and pods. Anyone who gains access to Kubelet agents can effectively control applications within the pods and containers. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for Kubelet, the parameter client-cert-auth must be set. This parameter gives the location of the SSL Certificate Authority file used to secure Kubelet communication.

Checks: C-45698r863857_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i client-cert-auth * If the setting client-cert-auth is not configured in the Kubernetes etcd manifest file or set to "false", this is a finding.

Fix: F-45656r863858_fix

Edit the Kubernetes etcd manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--client-cert-auth" to "true" for the etcd.

b

Kubernetes Kubelet must enable tls-private-key-file for client authentication to secure service.

SC-23 - Medium - CCI-001184 - V-242424 - SV-242424r863999_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001460

Vuln IDs

V-242424

Rule IDs

SV-242424r863999_rule

Kubernetes container and pod configuration are maintained by Kubelet. Kubelet agents register nodes with the API Server, mount volume storage, and perform health checks for containers and pods. Anyone who gains access to Kubelet agents can effectively control applications within the pods and containers. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for Kubelet, the tls-private-key-file must be set. This parameter gives the location of the SSL Certificate Authority file used to secure Kubelet communication.

Checks: C-45699r863860_chk

Change to the /etc/sysconfig/ directory on the Kubernetes Control Plane. Run the commands: grep -i tls-private-key-file kubelet If the setting "tls-private-key-file" is not configured in the Kubernetes Kubelet, this is a finding.

Fix: F-45657r863861_fix

Edit the Kubernetes Kubelet file in the /etc/sysconfig directory on the Kubernetes Control Plane. Set the argument tls-private-key-file to an Approved Organization Certificate. Reset Kubelet service using the following command: service kubelet restart

b

Kubernetes Kubelet must enable tls-cert-file for client authentication to secure service.

SC-23 - Medium - CCI-001184 - V-242425 - SV-242425r864000_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001470

Vuln IDs

V-242425

Rule IDs

SV-242425r864000_rule

Kubernetes container and pod configuration are maintained by Kubelet. Kubelet agents register nodes with the API Server, mount volume storage, and perform health checks for containers and pods. Anyone who gains access to Kubelet agents can effectively control applications within the pods and containers. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for Kubelet, the parameter etcd-cafile must be set. This parameter gives the location of the SSL Certificate Authority file used to secure Kubelet communication.

Checks: C-45700r863863_chk

Change to the /etc/sysconfig/ directory on the Kubernetes Control Plane. Run the command: grep -i tls-cert-file kubelet If the setting "tls-cert-file" is not configured in the Kubernetes Kubelet, this is a finding.

Fix: F-45658r863864_fix

Edit the Kubernetes Kubelet file in the /etc/sysconfig directory on the Kubernetes Control Plane. Set the argument "tls-cert-file" to an Approved Organization Certificate. Reset Kubelet service using the following command: service kubelet restart

b

Kubernetes etcd must enable client authentication to secure service.

SC-23 - Medium - CCI-001184 - V-242426 - SV-242426r864001_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001480

Vuln IDs

V-242426

Rule IDs

SV-242426r864001_rule

Kubernetes container and pod configuration are maintained by Kubelet. Kubelet agents register nodes with the API Server, mount volume storage, and perform health checks for containers and pods. Anyone who gains access to Kubelet agents can effectively control applications within the pods and containers. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server with a means to be able to authenticate sessions and encrypt traffic. Etcd is a highly-available key value store used by Kubernetes deployments for persistent storage of all of its REST API objects. These objects are sensitive and should be accessible only by authenticated etcd peers in the etcd cluster. The parameter peer-client-cert-auth must be set for etcd to check all incoming peer requests from the cluster for valid client certificates.

Checks: C-45701r863866_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i peer-client-cert-auth * If the setting peer-client-cert-auth is not configured in the Kubernetes etcd manifest file or set to "false", this is a finding.

Fix: F-45659r863867_fix

Edit the Kubernetes etcd file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--peer-client-cert-auth" to "true" for the etcd.

b

Kubernetes etcd must have a key file for secure communication.

SC-23 - Medium - CCI-001184 - V-242427 - SV-242427r864002_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001490

Vuln IDs

V-242427

Rule IDs

SV-242427r864002_rule

Kubernetes stores configuration and state information in a distributed key-value store called etcd. Anyone who can write to etcd can effectively control the Kubernetes cluster. Even just reading the contents of etcd could easily provide helpful hints to a would-be attacker. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server and etcd with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for etcd, the parameter key-file must be set. This parameter gives the location of the key file used to secure etcd communication.

Checks: C-45702r863869_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i key-file * If the setting "key-file" is not configured in the etcd manifest file, this is a finding.

Fix: F-45660r863870_fix

Edit the Kubernetes etcd manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--key-file" to the Approved Organizational Certificate.

b

Kubernetes etcd must have a certificate for communication.

SC-23 - Medium - CCI-001184 - V-242428 - SV-242428r864003_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001500

Vuln IDs

V-242428

Rule IDs

SV-242428r864003_rule

Kubernetes stores configuration and state information in a distributed key-value store called etcd. Anyone who can write to etcd can effectively control a Kubernetes cluster. Even just reading the contents of etcd could easily provide helpful hints to a would-be attacker. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server and etcd with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for etcd, the parameter cert-file must be set. This parameter gives the location of the SSL certification file used to secure etcd communication.

Checks: C-45703r863872_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i cert-file * If the setting "cert-file" is not configured in the Kubernetes etcd manifest file, this is a finding.

Fix: F-45661r863873_fix

Edit the Kubernetes etcd manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--cert-file" to the Approved Organizational Certificate.

b

Kubernetes etcd must have the SSL Certificate Authority set.

SC-23 - Medium - CCI-001184 - V-242429 - SV-242429r864004_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001510

Vuln IDs

V-242429

Rule IDs

SV-242429r864004_rule

Kubernetes stores configuration and state information in a distributed key-value store called etcd. Anyone who can write to etcd can effectively control a Kubernetes cluster. Even just reading the contents of etcd could easily provide helpful hints to a would-be attacker. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server and etcd with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for etcd, the parameter etcd-cafile must be set. This parameter gives the location of the SSL Certificate Authority file used to secure etcd communication.

Checks: C-45704r863875_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i etcd-cafile * If the setting "etcd-cafile" is not configured in the Kubernetes kube-apiserver manifest file, this is a finding.

Fix: F-45662r863876_fix

Edit the Kubernetes kube-apiserver manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--etcd-cafile" to the Certificate Authority for etcd.

b

Kubernetes etcd must have a certificate for communication.

SC-23 - Medium - CCI-001184 - V-242430 - SV-242430r864005_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001520

Vuln IDs

V-242430

Rule IDs

SV-242430r864005_rule

Kubernetes stores configuration and state information in a distributed key-value store called etcd. Anyone who can write to etcd can effectively control your Kubernetes cluster. Even just reading the contents of etcd could easily provide helpful hints to a would-be attacker. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server and etcd with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for etcd, the parameter etcd-certfile must be set. This parameter gives the location of the SSL certification file used to secure etcd communication.

Checks: C-45705r863878_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i etcd-certfile * If the setting "etcd-certfile" is not set in the Kubernetes kube-apiserver manifest file, this is a finding.

Fix: F-45663r863879_fix

Edit the Kubernetes kube-apiserver manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--etcd-certfile" to the certificate to be used for communication with etcd.

b

Kubernetes etcd must have a key file for secure communication.

SC-23 - Medium - CCI-001184 - V-242431 - SV-242431r864006_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001530

Vuln IDs

V-242431

Rule IDs

SV-242431r864006_rule

Kubernetes stores configuration and state information in a distributed key-value store called etcd. Anyone who can write to etcd can effectively control a Kubernetes cluster. Even just reading the contents of etcd could easily provide helpful hints to a would-be attacker. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server and etcd with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for etcd, the parameter etcd-keyfile must be set. This parameter gives the location of the key file used to secure etcd communication.

Checks: C-45706r863881_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i etcd-keyfile * If the setting "etcd-keyfile" is not configured in the Kubernetes kube-apiserver manifest file, this is a finding.

Fix: F-45664r863882_fix

Edit the Kubernetes kube-apiserver manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--etcd-keyfile" to the certificate to be used for communication with etcd.

b

Kubernetes etcd must have peer-cert-file set for secure communication.

SC-23 - Medium - CCI-001184 - V-242432 - SV-242432r864007_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001540

Vuln IDs

V-242432

Rule IDs

SV-242432r864007_rule

Kubernetes stores configuration and state information in a distributed key-value store called etcd. Anyone who can write to etcd can effectively control the Kubernetes cluster. Even just reading the contents of etcd could easily provide helpful hints to a would-be attacker. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server and etcd with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for etcd, the parameter peer-cert-file must be set. This parameter gives the location of the SSL certification file used to secure etcd communication.

Checks: C-45707r863884_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i peer-cert-file * If the setting "peer-cert-file" is not configured in the Kubernetes etcd manifest file, this is a finding.

Fix: F-45665r863885_fix

Edit the Kubernetes etcd manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--peer-cert-file" to the certificate to be used for communication with etcd.

b

Kubernetes etcd must have a peer-key-file set for secure communication.

SC-23 - Medium - CCI-001184 - V-242433 - SV-242433r864008_rule

RMF Control

SC-23

Severity

M

CCI

Version

CNTR-K8-001550

Vuln IDs

V-242433

Rule IDs

SV-242433r864008_rule

Kubernetes stores configuration and state information in a distributed key-value store called etcd. Anyone who can write to etcd can effectively control a Kubernetes cluster. Even just reading the contents of etcd could easily provide helpful hints to a would-be attacker. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server and etcd with a means to be able to authenticate sessions and encrypt traffic. To enable encrypted communication for etcd, the parameter peer-key-file must be set. This parameter gives the location of the SSL certification file used to secure etcd communication.

Checks: C-45708r863887_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i peer-key-file * If the setting "peer-key-file" is not set in the Kubernetes etcd manifest file, this is a finding.

Fix: F-45666r863888_fix

Edit the Kubernetes etcd manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--peer-key-file" to the certificate to be used for communication with etcd.

c

Kubernetes Kubelet must enable kernel protection.

SC-3 - High - CCI-001084 - V-242434 - SV-242434r864009_rule

RMF Control

SC-3

Severity

H

CCI

CCI-001084

Version

CNTR-K8-001620

Vuln IDs

V-242434

Rule IDs

SV-242434r864009_rule

System kernel is responsible for memory, disk, and task management. The kernel provides a gateway between the system hardware and software. Kubernetes requires kernel access to allocate resources to the Control Plane. Threat actors that penetrate the system kernel can inject malicious code or hijack the Kubernetes architecture. It is vital to implement protections through Kubernetes components to reduce the attack surface.

Checks: C-45709r863890_chk

Change to the /etc/sysconfig/ directory on the Kubernetes Control Plane. Run the command: grep -i protect-kernel-defaults kubelet If the setting "protect-kernel-defaults" is set to false or not set in the Kubernetes Kubelet, this is a finding.

Fix: F-45667r863891_fix

Edit the Kubernetes Kubelet file in the /etc/sysconfig directory on the Kubernetes Control Plane. Set the argument "--protect-kernel-defaults" to "true". Reset Kubelet service using the following command: service kubelet restart

c

Kubernetes must prevent non-privileged users from executing privileged functions to include disabling, circumventing, or altering implemented security safeguards/countermeasures or the installation of patches and updates.

AC-3 - High - CCI-000213 - V-242435 - SV-242435r864010_rule

RMF Control

AC-3

Severity

H

CCI

Version

CNTR-K8-001990

Vuln IDs

V-242435

Rule IDs

SV-242435r864010_rule

Kubernetes uses the API Server to control communication to the other services that makeup Kubernetes. The use of authorizations and not the default of "AlwaysAllow" enables the Kubernetes functions control to only the groups that need them. To control access the API server must have one of the following options set for the authorization mode: --authorization-mode=ABAC Attribute-Based Access Control (ABAC) mode allows a user to configure policies using local files. --authorization-mode=RBAC Role-based access control (RBAC) mode allows a user to create and store policies using the Kubernetes API. --authorization-mode=Webhook WebHook is an HTTP callback mode that allows a user to manage authorization using a remote REST endpoint. --authorization-mode=Node Node authorization is a special-purpose authorization mode that specifically authorizes API requests made by kubelets. --authorization-mode=AlwaysDeny This flag blocks all requests. Use this flag only for testing. Satisfies: SRG-APP-000340-CTR-000770, SRG-APP-000033-CTR-000095, SRG-APP-000378-CTR-000880

Checks: C-45710r863893_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i authorization-mode * If the setting authorization-mode is set to "AlwaysAllow" in the Kubernetes API Server manifest file or is not configured, this is a finding.

Fix: F-45668r863894_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the argument "--authorization-mode" to any valid authorization mode other than AlwaysAllow.

c

The Kubernetes API server must have the ValidatingAdmissionWebhook enabled.

AC-16 - High - CCI-002263 - V-242436 - SV-242436r864011_rule

RMF Control

AC-16

Severity

H

CCI

Version

CNTR-K8-002000

Vuln IDs

V-242436

Rule IDs

SV-242436r864011_rule

Enabling the admissions webhook allows for Kubernetes to apply policies against objects that are to be created, read, updated, or deleted. By applying a pod security policy, control can be given to not allow images to be instantiated that run as the root user. If pods run as the root user, the pod then has root privileges to the host system and all the resources it has. An attacker can use this to attack the Kubernetes cluster. By implementing a policy that does not allow root or privileged pods, the pod users are limited in what the pod can do and access.

Checks: C-45711r863896_chk

Prior to version 1.21, to enforce security policiesPod Security Policies (psp) were used. Those are now deprecated and will be removed from version 1.25. Migrate from PSP to PSA: https://kubernetes.io/docs/tasks/configure-pod-container/migrate-from-psp/ Pre-version 1.25 Check: Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i ValidatingAdmissionWebhook * If a line is not returned that includes enable-admission-plugins and ValidatingAdmissionWebhook, this is a finding.

Fix: F-45669r863897_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the argument "--enable-admission-plugins" to include "ValidatingAdmissionWebhook". Each enabled plugin is separated by commas. Note: It is best to implement policies first and then enable the webhook, otherwise a denial of service may occur.

c

Kubernetes must have a pod security policy set.

AC-16 - High - CCI-002263 - V-242437 - SV-242437r864012_rule

RMF Control

AC-16

Severity

H

CCI

Version

CNTR-K8-002010

Vuln IDs

V-242437

Rule IDs

SV-242437r864012_rule

Enabling the admissions webhook allows for Kubernetes to apply policies against objects that are to be created, read, updated, or deleted. By applying a pod security policy, control can be given to not allow images to be instantiated that run as the root user. If pods run as the root user, the pod then has root privileges to the host system and all the resources it has. An attacker can use this to attack the Kubernetes cluster. By implementing a policy that does not allow root or privileged pods, the pod users are limited in what the pod can do and access.

Checks: C-45712r863899_chk

Prior to version 1.21, to enforce security policiesPod Security Policies (psp) were used. Those are now deprecated and will be removed from version 1.25. Migrate from PSP to PSA: https://kubernetes.io/docs/tasks/configure-pod-container/migrate-from-psp/ Pre-version 1.25 Check: On the Control Plane, run the command: kubectl get podsecuritypolicy If there is no pod security policy configured, this is a finding. For any pod security policies listed, edit the policy with the command: kubectl edit podsecuritypolicy policyname (Note: "policyname" is the name of the policy.) Review the runAsUser, supplementalGroups and fsGroup sections of the policy. If any of these sections are missing, this is a finding. If the rule within the runAsUser section is not set to "MustRunAsNonRoot", this is a finding. If the ranges within the supplementalGroups section has min set to "0" or min is missing, this is a finding. If the ranges within the fsGroup section has a min set to "0" or the min is missing, this is a finding.

Fix: F-45670r863900_fix

From the Control Plane, save the following policy to a file called restricted.yml. apiVersion: policy/v1beta1 kind: PodSecurityPolicy metadata: name: restricted annotations: apparmor.security.beta.kubernetes.io/allowedProfileNames: 'runtime/default', seccomp.security.alpha.kubernetes.io/defaultProfileName: 'runtime/default', apparmor.security.beta.kubernetes.io/defaultProfileName: 'runtime/default' spec: privileged: false # Required to prevent escalations to root. allowPrivilegeEscalation: false # This is redundant with non-root + disallow privilege escalation, # but we can provide it for defense in depth. requiredDropCapabilities: - ALL # Allow core volume types. volumes: - 'configMap' - 'emptyDir' - 'projected' - 'secret' - 'downwardAPI' # Assume that persistentVolumes set up by the cluster admin are safe to use. - 'persistentVolumeClaim' hostNetwork: false hostIPC: false hostPID: false runAsUser: # Require the container to run without root privileges. rule: 'MustRunAsNonRoot' seLinux: # This policy assumes the nodes are using AppArmor rather than SELinux. rule: 'RunAsAny' supplementalGroups: rule: 'MustRunAs' ranges: # Forbid adding the root group. - min: 1 max: 65535 fsGroup: rule: 'MustRunAs' ranges: # Forbid adding the root group. - min: 1 max: 65535 readOnlyRootFilesystem: false To implement the policy, run the command: kubectl create -f restricted.yml

b

Kubernetes API Server must configure timeouts to limit attack surface.

SC-7 - Medium - CCI-002415 - V-242438 - SV-242438r864013_rule

RMF Control

SC-7

Severity

M

CCI

CCI-002415

Version

CNTR-K8-002600

Vuln IDs

V-242438

Rule IDs

SV-242438r864013_rule

Kubernetes API Server request timeouts sets the duration a request stays open before timing out. Since the API Server is the central component in the Kubernetes Control Plane, it is vital to protect this service. If request timeouts were not set, malicious attacks or unwanted activities might affect multiple deployments across different applications or environments. This might deplete all resources from the Kubernetes infrastructure causing the information system to go offline. The request-timeout value must never be set to "0". This disables the request-timeout feature. By default, the request-timeout is set to "1 minute".

Checks: C-45713r863902_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -I request-timeout * If Kubernetes API Server manifest file does not exist, this is a finding. If the setting request-timeout is set to "0" in the Kubernetes API Server manifest file, or is not configured this is a finding.

Fix: F-45671r863903_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of request-timeout greater than "0".

b

Kubernetes must remove old components after updated versions have been installed.

SI-4 - Medium - CCI-002647 - V-242442 - SV-242442r878098_rule

RMF Control

SI-4

Severity

M

CCI

CCI-002647

Version

CNTR-K8-002700

Vuln IDs

V-242442

Rule IDs

SV-242442r878098_rule

Previous versions of Kubernetes components that are not removed after updates have been installed may be exploited by adversaries by allowing the vulnerabilities to still exist within the cluster. It is important for Kubernetes to remove old pods when newer pods are created using new images to always be at the desired security state.

Checks: C-45717r863905_chk

To view all pods and the images used to create the pods, from the Control Plane, run the following command: kubectl get pods --all-namespaces -o jsonpath="{..image}" | \ tr -s '[[:space:]]' '\n' | \ sort | \ uniq -c Review the images used for pods running within Kubernetes. If there are multiple versions of the same image, this is a finding.

Fix: F-45675r863906_fix

Remove any old pods that are using older images. On the Control Plane, run the command: kubectl delete pod podname (Note: "podname" is the name of the pod to delete.)

b

Kubernetes must contain the latest updates as authorized by IAVMs, CTOs, DTMs, and STIGs.

SI-3 - Medium - CCI-002635 - V-242443 - SV-242443r864015_rule

RMF Control

SI-3

Severity

M

CCI

CCI-002635

Version

CNTR-K8-002720

Vuln IDs

V-242443

Rule IDs

SV-242443r864015_rule

Kubernetes software must stay up to date with the latest patches, service packs, and hot fixes. Not updating the Kubernetes control plane will expose the organization to vulnerabilities. Flaws discovered during security assessments, continuous monitoring, incident response activities, or information system error handling must also be addressed expeditiously. Organization-defined time periods for updating security-relevant container platform components may vary based on a variety of factors including, for example, the security category of the information system or the criticality of the update (i.e., severity of the vulnerability related to the discovered flaw). This requirement will apply to software patch management solutions that are used to install patches across the enclave and also to applications themselves that are not part of that patch management solution. For example, many browsers today provide the capability to install their own patch software. Patch criticality, as well as system criticality will vary. Therefore, the tactical situations regarding the patch management process will also vary. This means that the time period utilized must be a configurable parameter. Time frames for application of security-relevant software updates may be dependent upon the IAVM process. The container platform components will be configured to check for and install security-relevant software updates within an identified time period from the availability of the update. The container platform registry will ensure the images are current. The specific time period will be defined by an authoritative source (e.g., IAVM, CTOs, DTMs, and STIGs).

Checks: C-45718r863908_chk

Authenticate on the Kubernetes Control Plane. Run the command: kubectl version --short If kubectl version has a setting not supporting Kubernetes skew policy, this is a finding. Note: Kubernetes Skew Policy can be found at: https://kubernetes.io/docs/setup/release/version-skew-policy/#supported-versions

Fix: F-45676r712684_fix

Upgrade Kubernetes to the supported version. Institute and adhere to the policies and procedures to ensure that patches are consistently applied within the time allowed.

b

The Kubernetes component manifests must be owned by root.

CM-6 - Medium - CCI-000366 - V-242444 - SV-242444r864016_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003110

Vuln IDs

V-242444

Rule IDs

SV-242444r864016_rule

The Kubernetes manifests are those files that contain the arguments and settings for the Control Plane services. These services are etcd, the api server, controller, proxy, and scheduler. If these files can be changed, the scheduler will be implementing the changes immediately. Many of the security settings within the document are implemented through these manifests.

Checks: C-45719r712686_chk

Review the ownership of the Kubernetes manifests files by using the command: stat -c %U:%G /etc/kubernetes/manifests/* | grep -v root:root If the command returns any non root:root file permissions, this is a finding.

Fix: F-45677r712687_fix

Change the ownership of the manifest files to root: root by executing the command: chown root:root /etc/kubernetes/manifests/*

b

The Kubernetes component etcd must be owned by etcd.

CM-6 - Medium - CCI-000366 - V-242445 - SV-242445r864017_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003120

Vuln IDs

V-242445

Rule IDs

SV-242445r864017_rule

The Kubernetes etcd key-value store provides a way to store data to the Control Plane. If these files can be changed, data to API object and the Control Plane would be compromised. The scheduler will implement the changes immediately. Many of the security settings within the document are implemented through this file.

Checks: C-45720r712689_chk

Review the ownership of the Kubernetes etcd files by using the command: stat -c %U:%G /var/lib/etcd/* | grep -v etcd:etcd If the command returns any non etcd:etcd file permissions, this is a finding.

Fix: F-45678r712690_fix

Change the ownership of the manifest files to etcd:etcd by executing the command: chown etcd:etcd /var/lib/etcd/*

b

The Kubernetes conf files must be owned by root.

CM-6 - Medium - CCI-000366 - V-242446 - SV-242446r864018_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003130

Vuln IDs

V-242446

Rule IDs

SV-242446r864018_rule

The Kubernetes conf files contain the arguments and settings for the Control Plane services. These services are controller and scheduler. If these files can be changed, the scheduler will be implementing the changes immediately. Many of the security settings within the document are implemented through this file.

Checks: C-45721r712692_chk

Review the Kubernetes conf files by using the command: stat -c %U:%G /etc/kubernetes/admin.conf | grep -v root:root stat -c %U:%G /etc/kubernetes/scheduler.conf | grep -v root:root stat -c %U:%G /etc/kubernetes/controller-manager.conf | grep -v root:root If the command returns any non root:root file permissions, this is a finding.

Fix: F-45679r712693_fix

Change the ownership of the conf files to root: root by executing the command: chown root:root /etc/kubernetes/admin.conf chown root:root /etc/kubernetes/scheduler.conf chown root:root /etc/kubernetes/controller-manager.conf

b

The Kubernetes Kube Proxy must have file permissions set to 644 or more restrictive.

CM-6 - Medium - CCI-000366 - V-242447 - SV-242447r864019_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003140

Vuln IDs

V-242447

Rule IDs

SV-242447r864019_rule

The Kubernetes kube proxy kubeconfig contain the argument and setting for the Control Planes. These settings contain network rules for restricting network communication between pods, clusters, and networks. If these files can be changed, data traversing between the Kubernetes Control Panel components would be compromised. Many of the security settings within the document are implemented through this file.

Checks: C-45722r712695_chk

Check if Kube-Proxy is running and obtain --kubeconfig parameter use the following command: ps -ef | grep kube-proxy If Kube-Proxy exists: Review the permissions of the Kubernetes Kube Proxy by using the command: stat -c %a <location from --kubeconfig> If the file has permissions more permissive than "644", this is a finding.

Fix: F-45680r821611_fix

Change the permissions of the Kube Proxy to "644" by executing the command: chmod 644 <location from kubeconfig>.

b

The Kubernetes Kube Proxy must be owned by root.

CM-6 - Medium - CCI-000366 - V-242448 - SV-242448r864020_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003150

Vuln IDs

V-242448

Rule IDs

SV-242448r864020_rule

The Kubernetes kube proxy kubeconfig contain the argument and setting for the Control Planes. These settings contain network rules for restricting network communication between pods, clusters, and networks. If these files can be changed, data traversing between the Kubernetes Control Panel components would be compromised. Many of the security settings within the document are implemented through this file.

Checks: C-45723r712698_chk

Check if Kube-Proxy is running use the following command: ps -ef | grep kube-proxy If Kube-Proxy exists: Review the permissions of the Kubernetes Kube Proxy by using the command: stat -c %U:%G <location from --kubeconfig>| grep -v root:root If the command returns any non root:root file permissions, this is a finding.

Fix: F-45681r712699_fix

Change the ownership of the Kube Proxy to root:root by executing the command: chown root:root <location from kubeconfig>.

b

The Kubernetes Kubelet certificate authority file must have file permissions set to 644 or more restrictive.

CM-6 - Medium - CCI-000366 - V-242449 - SV-242449r864021_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003160

Vuln IDs

V-242449

Rule IDs

SV-242449r864021_rule

The Kubernetes kubelet certificate authority file contains settings for the Kubernetes Node TLS certificate authority. Any request presenting a client certificate signed by one of the authorities in the client-ca-file is authenticated with an identity corresponding to the CommonName of the client certificate. If this file can be changed, the Kubernetes architecture could be compromised. The scheduler will implement the changes immediately. Many of the security settings within the document are implemented through this file.

Checks: C-45724r863915_chk

Change to the /etc/sysconfig/ directory on the Kubernetes Control Plane. Run command: more kubelet --client-ca-file argument Note certificate location If the ca-file argument location file has permissions more permissive than "644", this is a finding.

Fix: F-45682r821613_fix

Change the permissions of the --client-ca-file to "644" by executing the command: chmod 644 <kubelet --client--ca-file argument location>.

b

The Kubernetes Kubelet certificate authority must be owned by root.

CM-6 - Medium - CCI-000366 - V-242450 - SV-242450r864022_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003170

Vuln IDs

V-242450

Rule IDs

SV-242450r864022_rule

The Kubernetes kube proxy kubeconfig contain the argument and setting for the Control Planes. These settings contain network rules for restricting network communication between pods, clusters, and networks. If these files can be changed, data traversing between the Kubernetes Control Panel components would be compromised. Many of the security settings within the document are implemented through this file.

Checks: C-45725r863917_chk

Change to the /etc/sysconfig/ directory on the Kubernetes Control Plane. Review the ownership of the Kubernetes client-ca-file by using the command: more kubelet --client-ca-file argument Note certificate location Review the ownership of the Kubernetes client-ca-file by using the command: stat -c %U:%G <location from --client-ca-file argument>| grep -v root:root If the command returns any non root:root file permissions, this is a finding.

Fix: F-45683r712705_fix

Change the permissions of the Kube Proxy to "root" by executing the command: chown root:root <location from kubeconfig>.

b

The Kubernetes component PKI must be owned by root.

CM-6 - Medium - CCI-000366 - V-242451 - SV-242451r712709_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003180

Vuln IDs

V-242451

Rule IDs

SV-242451r712709_rule

The Kubernetes PKI directory contains all certificates (.crt files) supporting secure network communications in the Kubernetes Control Plane. If these files can be modified, data traversing within the architecture components would become unsecure and compromised. Many of the security settings within the document are implemented through this file.

Checks: C-45726r712707_chk

Review the PKI files in Kubernetes by using the command: ls -laR /etc/kubernetes/pki/ If the command returns any non root:root file permissions, this is a finding.

Fix: F-45684r712708_fix

Change the ownership of the PKI to root: root by executing the command: chown -R root:root /etc/kubernetes/pki/

b

The Kubernetes kubelet config must have file permissions set to 644 or more restrictive.

CM-6 - Medium - CCI-000366 - V-242452 - SV-242452r821616_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003190

Vuln IDs

V-242452

Rule IDs

SV-242452r821616_rule

The Kubernetes kubelet agent registers nodes with the API Server, mounts volume storage for pods, and performs health checks to containers within pods. If these files can be modified, the information system would be unaware of pod or container degradation. Many of the security settings within the document are implemented through this file.

Checks: C-45727r712710_chk

Review the permissions of the Kubernetes Kubelet conf by using the command: stat -c %a /etc/kubernetes/kubelet.conf If any of the files are have permissions more permissive than "644", this is a finding.

Fix: F-45685r821615_fix

Change the permissions of the Kubelet to "644" by executing the command: chmod 644 /etc/kubernetes/kubelet.conf

b

The Kubernetes kubelet config must be owned by root.

CM-6 - Medium - CCI-000366 - V-242453 - SV-242453r712715_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003200

Vuln IDs

V-242453

Rule IDs

SV-242453r712715_rule

The Kubernetes kubelet agent registers nodes with the API server and performs health checks to containers within pods. If these files can be modified, the information system would be unaware of pod or container degradation. Many of the security settings within the document are implemented through this file.

Checks: C-45728r712713_chk

Review the Kubernetes Kubelet conf files by using the command: stat -c %U:%G /etc/kubernetes/kubelet.conf| grep -v root:root If the command returns any non root:root file permissions, this is a finding.

Fix: F-45686r712714_fix

Change the ownership of the kubelet.conf to root: root by executing the command: chown root:root /etc/kubernetes/kubelet.conf

b

The Kubernetes kubeadm.conf must be owned by root.

CM-6 - Medium - CCI-000366 - V-242454 - SV-242454r754819_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003210

Vuln IDs

V-242454

Rule IDs

SV-242454r754819_rule

The Kubernetes kubeeadm.conf contains sensitive information regarding the cluster nodes configuration. If this file can be modified, the Kubernetes Platform Plane would be degraded or compromised for malicious intent. Many of the security settings within the document are implemented through this file.

Checks: C-45729r754817_chk

Review the Kubeadm.conf file : Get the path for Kubeadm.conf by running: sytstemctl status kubelet Note the configuration file installed by the kubeadm is written to (Default Location: /etc/systemd/system/kubelet.service.d/10-kubeadm.conf) stat -c %U:%G <kubeadm.conf path> | grep -v root:root If the command returns any non root:root file permissions, this is a finding.

Fix: F-45687r754818_fix

Change the ownership of the kubeadm.conf to root: root by executing the command: chown root:root <kubeadm.conf path>

b

The Kubernetes kubeadm.conf must have file permissions set to 644 or more restrictive.

CM-6 - Medium - CCI-000366 - V-242455 - SV-242455r754822_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003220

Vuln IDs

V-242455

Rule IDs

SV-242455r754822_rule

The Kubernetes kubeadm.conf contains sensitive information regarding the cluster nodes configuration. If this file can be modified, the Kubernetes Platform Plane would be degraded or compromised for malicious intent. Many of the security settings within the document are implemented through this file.

Checks: C-45730r754820_chk

Review the kubeadm.conf file : Get the path for kubeadm.conf by running: systemctl status kubelet Note the configuration file installed by the kubeadm is written to (Default Location: /etc/systemd/system/kubelet.service.d/10-kubeadm.conf) stat -c %a <kubeadm.conf path> If the file has permissions more permissive than "644", this is a finding.

Fix: F-45688r754821_fix

Change the permissions of kubeadm.conf to "644" by executing the command: chmod 644 <kubeadm.conf path>

b

The Kubernetes kubelet config must have file permissions set to 644 or more restrictive.

CM-6 - Medium - CCI-000366 - V-242456 - SV-242456r821618_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003230

Vuln IDs

V-242456

Rule IDs

SV-242456r821618_rule

The Kubernetes kubelet agent registers nodes with the API server and performs health checks to containers within pods. If this file can be modified, the information system would be unaware of pod or container degradation.

Checks: C-45731r712722_chk

Review the permissions of the Kubernetes config.yaml by using the command: stat -c %a /var/lib/kubelet/config.yaml If any of the files are have permissions more permissive than "644", this is a finding.

Fix: F-45689r821617_fix

Change the permissions of the config.yaml to "644" by executing the command: chmod 644 /var/lib/kubelet/config.yaml

b

The Kubernetes kubelet config must be owned by root.

CM-6 - Medium - CCI-000366 - V-242457 - SV-242457r712727_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003240

Vuln IDs

V-242457

Rule IDs

SV-242457r712727_rule

The Kubernetes kubelet agent registers nodes with the API Server and performs health checks to containers within pods. If this file can be modified, the information system would be unaware of pod or container degradation.

Checks: C-45732r712725_chk

Review the Kubernetes Kubeadm kubelet conf file by using the command: stat -c %U:%G /var/lib/kubelet/config.yaml| grep -v root:root If the command returns any non root:root file permissions, this is a finding.

Fix: F-45690r712726_fix

Change the ownership of the kubelet config to "root: root" by executing the command: chown root:root /var/lib/kubelet/config.yaml

b

The Kubernetes API Server must have file permissions set to 644 or more restrictive.

CM-6 - Medium - CCI-000366 - V-242458 - SV-242458r864023_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003250

Vuln IDs

V-242458

Rule IDs

SV-242458r864023_rule

The Kubernetes manifests are those files that contain the arguments and settings for the Control Plane services. These services are etcd, the API Server, controller, proxy, and scheduler. If these files can be changed, the scheduler will be implementing the changes immediately. Many of the security settings within the document are implemented through these manifests.

Checks: C-45733r712728_chk

Review the permissions of the Kubernetes Kubelet by using the command: stat -c %a /etc/kubernetes/manifests/* If any of the files are have permissions more permissive than "644", this is a finding.

Fix: F-45691r754805_fix

Change the permissions of the manifest files by executing the command: chmod 644 /etc/kubernetes/manifests/*

b

The Kubernetes etcd must have file permissions set to 644 or more restrictive.

CM-6 - Medium - CCI-000366 - V-242459 - SV-242459r864024_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003260

Vuln IDs

V-242459

Rule IDs

SV-242459r864024_rule

The Kubernetes etcd key-value store provides a way to store data to the Control Plane. If these files can be changed, data to API object and Control Plane would be compromised.

Checks: C-45734r712731_chk

Review the permissions of the Kubernetes etcd by using the command: stat -c %a /var/lib/etcd/* If any of the files are have permissions more permissive than "644", this is a finding.

Fix: F-45692r712732_fix

Change the permissions of the manifest files to "644" by executing the command: chmod 644/var/lib/etcd/*

b

The Kubernetes admin.conf must have file permissions set to 644 or more restrictive.

CM-6 - Medium - CCI-000366 - V-242460 - SV-242460r864025_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003270

Vuln IDs

V-242460

Rule IDs

SV-242460r864025_rule

The Kubernetes conf files contain the arguments and settings for the Control Plane services. These services are controller and scheduler. If these files can be changed, the scheduler will be implementing the changes immediately.

Checks: C-45735r712734_chk

Review the permissions of the Kubernetes config files by using the command: stat -c %a /etc/kubernetes/admin.conf stat -c %a /etc/kubernetes/scheduler.conf stat -c %a /etc/kubernetes/controller-manager.conf If any of the files are have permissions more permissive than "644", this is a finding.

Fix: F-45693r712735_fix

Change the permissions of the conf files to "644" by executing the command: chmod 644 /etc/kubernetes/admin.conf chmod 644 /etc/kubernetes/scheduler.conf chmod 644 /etc/kubernetes/controller-manager.conf

b

Kubernetes API Server audit logs must be enabled.

CM-6 - Medium - CCI-000366 - V-242461 - SV-242461r864026_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003280

Vuln IDs

V-242461

Rule IDs

SV-242461r864026_rule

Kubernetes API Server validates and configures pods and services for the API object. The REST operation provides frontend functionality to the cluster share state. Enabling audit logs provides a way to monitor and identify security risk events or misuse of information. Audit logs are necessary to provide evidence in the case the Kubernetes API Server is compromised requiring a Cyber Security Investigation.

Checks: C-45736r863922_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i audit-policy-file * If the setting "audit-policy-file" is not set or is found in the Kubernetes API manifest file without valid content, this is a finding.

Fix: F-45694r863923_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the argument "--audit-policy-file" to "log file directory".

b

The Kubernetes API Server must be set to audit log max size.

CM-6 - Medium - CCI-000366 - V-242462 - SV-242462r864027_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003290

Vuln IDs

V-242462

Rule IDs

SV-242462r864027_rule

The Kubernetes API Server must be set for enough storage to retain log information over the period required. When audit logs are large in size, the monitoring service for events becomes degraded. The function of the maximum log file size is to set these limits.

Checks: C-45737r863925_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i audit-log-maxsize * If the setting "audit-log-maxsize" is not set in the Kubernetes API Server manifest file or it is set to less than "100", this is a finding.

Fix: F-45695r863926_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of –"--audit-log-maxsize" to a minimum of "100".

b

The Kubernetes API Server must be set to audit log maximum backup.

CM-6 - Medium - CCI-000366 - V-242463 - SV-242463r864028_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003300

Vuln IDs

V-242463

Rule IDs

SV-242463r864028_rule

The Kubernetes API Server must set enough storage to retain logs for monitoring suspicious activity and system misconfiguration, and provide evidence for Cyber Security Investigations.

Checks: C-45738r863928_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i audit-log-maxbackup * If the setting "audit-log-maxbackup" is not set in the Kubernetes API Server manifest file or it is set less than "10", this is a finding.

Fix: F-45696r863929_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--audit-log-maxbackup" to a minimum of "10".

b

The Kubernetes API Server audit log retention must be set.

CM-6 - Medium - CCI-000366 - V-242464 - SV-242464r864029_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003310

Vuln IDs

V-242464

Rule IDs

SV-242464r864029_rule

The Kubernetes API Server must set enough storage to retain logs for monitoring suspicious activity and system misconfiguration, and provide evidence for Cyber Security Investigations.

Checks: C-45739r863931_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i audit-log-maxage * If the setting "audit-log-maxage" is not set in the Kubernetes API Server manifest file or it is set less than "30", this is a finding.

Fix: F-45697r863932_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--audit-log-maxage" to a minimum of "30".

b

The Kubernetes API Server audit log path must be set.

CM-6 - Medium - CCI-000366 - V-242465 - SV-242465r864030_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003320

Vuln IDs

V-242465

Rule IDs

SV-242465r864030_rule

Kubernetes API Server validates and configures pods and services for the API object. The REST operation provides frontend functionality to the cluster share state. Audit logs are necessary to provide evidence in the case the Kubernetes API Server is compromised requiring Cyber Security Investigation. To record events in the audit log the log path value must be set.

Checks: C-45740r863934_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i audit-log-path * If the setting audit-log-path is not set in the Kubernetes API Server manifest file or it is not set to a valid path, this is a finding.

Fix: F-45698r863935_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--audit-log-path" to valid location.

b

The Kubernetes PKI CRT must have file permissions set to 644 or more restrictive.

CM-6 - Medium - CCI-000366 - V-242466 - SV-242466r712754_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003330

Vuln IDs

V-242466

Rule IDs

SV-242466r712754_rule

The Kubernetes PKI directory contains all certificates (.crt files) supporting secure network communications in the Kubernetes Control Plane. If these files can be modified, data traversing within the architecture components would become unsecure and compromised.

Checks: C-45741r712752_chk

Review the permissions of the Kubernetes PKI cert files by using the command: find /etc/kubernetes/pki -name "*.crt" | xargs stat -c '%n %a' If any of the files are have permissions more permissive than "644", this is a finding.

Fix: F-45699r712753_fix

Change the ownership of the cert files to "644" by executing the command: chmod -R 644 /etc/kubernetes/pki/*.crt

b

The Kubernetes PKI keys must have file permissions set to 600 or more restrictive.

CM-6 - Medium - CCI-000366 - V-242467 - SV-242467r878165_rule

RMF Control

CM-6

Severity

M

CCI

Version

CNTR-K8-003340

Vuln IDs

V-242467

Rule IDs

SV-242467r878165_rule

The Kubernetes PKI directory contains all certificate key files supporting secure network communications in the Kubernetes Control Plane. If these files can be modified, data traversing within the architecture components would become unsecure and compromised.

Checks: C-45742r878164_chk

Review the permissions of the Kubernetes PKI key files by using the command: sudo find /etc/kubernetes/pki/* -name "*.key" | xargs stat -c '%n %a' If any of the files are have permissions more permissive than "600", this is a finding.

Fix: F-45700r712756_fix

Change the ownership of the cert files to "600" by executing the command: chmod -R 600 /etc/kubernetes/pki/*.key

b

The Kubernetes API Server must prohibit communication using TLS version 1.0 and 1.1, and SSL 2.0 and 3.0.

AC-17 - Medium - CCI-001453 - V-242468 - SV-242468r864031_rule

RMF Control

AC-17

Severity

M

CCI

CCI-001453

Version

CNTR-K8-003350

Vuln IDs

V-242468

Rule IDs

SV-242468r864031_rule

The Kubernetes API Server will prohibit the use of SSL and unauthorized versions of TLS protocols to properly secure communication. The use of unsupported protocol exposes vulnerabilities to Kubernetes by rogue traffic interceptions, man-in-the middle attacks, and impersonation of users or services from the container platform runtime, registry, and keystore. To enable the minimum version of TLS to be used by the Kubernetes API Server, the setting "tls-min-version" must be set. The container platform and its components will adhere to NIST 800-52R2.

Checks: C-45743r863937_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: grep -i tls-min-version * If the setting tls-min-version is not configured in the Kubernetes API Server manifest file or it is set to "VersionTLS10" or "VersionTLS11", this is a finding.

Fix: F-45701r863938_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--tls-min-version" to either "VersionTLS12" or higher.

b

Kubernetes Kubelet must not disable timeouts.

SC-10 - Medium - CCI-001133 - V-245541 - SV-245541r864032_rule

RMF Control

SC-10

Severity

M

CCI

CCI-001133

Version

CNTR-K8-001300

Vuln IDs

V-245541

Rule IDs

SV-245541r864032_rule

Idle connections from the Kubelet can be used by unauthorized users to perform malicious activity to the nodes, pods, containers, and cluster within the Kubernetes Control Plane. Setting the streaming connection idle timeout defines the maximum time an idle session is permitted prior to disconnect. Setting the value to "0" never disconnects any idle sessions. Idle timeouts must never be set to "0" and should be defined at "5m" (the default is 4hr).

Checks: C-48816r863940_chk

On the Kubernetes Control Plane, run the command: ps -ef | grep kubelet Check the config file (path identified by: --config): Change to the directory identified by --config (example /etc/sysconfig/) run the command: grep -i streaming-connection-idle-timeout kubelet If the setting streaming-connection-idle-timeout is set to < "5m" or the parameter is not configured in the Kubernetes Kubelet, this is a finding.

Fix: F-48771r863941_fix

Edit the Kubernetes Kubelet file in the --config directory on the Kubernetes Control Plane: Set the argument "--streaming-connection-idle-timeout" to a value of "5m". Reset Kubelet service using the following command: service kubelet restart

c

Kubernetes API Server must disable basic authentication to protect information in transit.

SC-12 - High - CCI-002448 - V-245542 - SV-245542r864033_rule

RMF Control

SC-12

Severity

H

CCI

CCI-002448

Version

CNTR-K8-002620

Vuln IDs

V-245542

Rule IDs

SV-245542r864033_rule

Kubernetes basic authentication sends and receives request containing username, uid, groups, and other fields over a clear text HTTP communication. Basic authentication does not provide any security mechanisms using encryption standards. PKI certificate-based authentication must be set over a secure channel to ensure confidentiality and integrity. Basic authentication must not be set in the manifest file.

Checks: C-48817r863943_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i basic-auth-file * If "basic-auth-file" is set in the Kubernetes API server manifest file this is a finding.

Fix: F-48772r863944_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Remove the setting "--basic-auth-file".

b

Kubernetes API Server must disable token authentication to protect information in transit.

SC-12 - Medium - CCI-002448 - V-245543 - SV-245543r864034_rule

RMF Control

SC-12

Severity

M

CCI

CCI-002448

Version

CNTR-K8-002630

Vuln IDs

V-245543

Rule IDs

SV-245543r864034_rule

Kubernetes token authentication uses password known as secrets in a plaintext file. This file contains sensitive information such as token, username and user uid. This token is used by service accounts within pods to authenticate with the API Server. This information is very valuable for attackers with malicious intent if the service account is privileged having access to the token. With this token a threat actor can impersonate the service account gaining access to the Rest API service.

Checks: C-48818r863946_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i token-auth-file * If "token-auth-file" is set in the Kubernetes API server manifest file, this is a finding.

Fix: F-48773r863947_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Remove parameter "--token-auth-file".

b

Kubernetes endpoints must use approved organizational certificate and key pair to protect information in transit.

SC-12 - Medium - CCI-002448 - V-245544 - SV-245544r864035_rule

RMF Control

SC-12

Severity

M

CCI

CCI-002448

Version

CNTR-K8-002640

Vuln IDs

V-245544

Rule IDs

SV-245544r864035_rule

Kubernetes control plane and external communication is managed by API Server. The main implementation of the API Server is to manage hardware resources for pods and container using horizontal or vertical scaling. Anyone who can gain access to the API Server can effectively control your Kubernetes architecture. Using authenticity protection, the communication can be protected against man-in-the-middle attacks/session hijacking and the insertion of false information into sessions. The communication session is protected by utilizing transport encryption protocols, such as TLS. TLS provides the Kubernetes API Server with a means to be able to authenticate sessions and encrypt traffic. By default, the API Server does not authenticate to the kubelet HTTPs endpoint. To enable secure communication for API Server, the parameter -kubelet-client-certificate and kubelet-client-key must be set. This parameter gives the location of the certificate and key pair used to secure API Server communication.

Checks: C-48819r863949_chk

Change to the /etc/kubernetes/manifests/ directory on the Kubernetes Control Plane. Run the command: grep -i kubelet-client-certificate * grep -I kubelet-client-key * If the setting "--kubelet-client-certificate" is not configured in the Kubernetes API server manifest file or contains no value, this is a finding. If the setting "--kubelet-client-key" is not configured in the Kubernetes API server manifest file or contains no value, this is a finding.

Fix: F-48774r863950_fix

Edit the Kubernetes API Server manifest file in the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Set the value of "--kubelet-client-certificate" and "--kubelet-client-key" to an Approved Organizational Certificate and key pair.

c

Kubernetes must have a Pod Security Admission control file configured.

AC-16 - High - CCI-002263 - V-254800 - SV-254800r864040_rule

RMF Control

AC-16

Severity

H

CCI

Version

CNTR-K8-002011

Vuln IDs

V-254800

Rule IDs

SV-254800r864040_rule

An admission controller intercepts and processes requests to the Kubernetes API prior to persistence of the object, but after the request is authenticated and authorized. Kubernetes (> v1.23)offers a built-in Pod Security admission controller to enforce the Pod Security Standards. Pod security restrictions are applied at the namespace level when pods are created. The Kubernetes Pod Security Standards define different isolation levels for Pods. These standards let you define how you want to restrict the behavior of pods in a clear, consistent fashion.

Checks: C-58411r863727_chk

Change to the /etc/kubernetes/manifests directory on the Kubernetes Control Plane. Run the command: "grep -i admission-control-config-file *" If the setting "admission-control-config-file" is not configured in the Kubernetes API Server manifest file, this is a finding. Inspect the .yaml file defined by the --admission-control-config-file. Verify PodSecurity is properly configured. If least privilege is not represented, this is a finding.

Fix: F-58357r863728_fix

Modify the file /etc/kubernetes/manifests/kube-apiserver.yaml and add the flag --admission-control-config-file (with a valid path for the file) to the apiserver configuration. Create an admission controller config file: Example File: ```yaml apiVersion: apiserver.config.k8s.io/v1 kind: AdmissionConfiguration plugins: - name: PodSecurity configuration: apiVersion: pod-security.admission.config.k8s.io/v1beta1 kind: PodSecurityConfiguration # Defaults applied when a mode label is not set. defaults: enforce: "privileged" enforce-version: "latest" exemptions: # Don't forget to exempt namespaces or users that are responsible for deploying # cluster components, because they need to run privileged containers usernames: ["admin"] namespaces: ["kube-system"] See For More Details: Migrate from PSP to PSA: https://kubernetes.io/docs/tasks/configure-pod-container/migrate-from-psp/ Best Practice: https://kubernetes.io/docs/concepts/security/pod-security-policy/#recommended-practice

c

Kubernetes must have a Pod Security Admission feature gate set.

AC-16 - High - CCI-002263 - V-254801 - SV-254801r864044_rule

RMF Control

AC-16

Severity

H

CCI