Title

Configuration and authentication files for Rancher RKE2 must be protected. (Cat II impact)

Discussion

There are various configuration files, logs, access credentials, and other files stored on the host filesystem that contain sensitive information. These files could potentially put at risk, along with other specific workloads and components: - API server. - proxy. - scheduler. - controller. - etcd. - Kubernetes administrator account information. - audit log access, modification, and deletion. - application access, modification, and deletion. - container runtime files. 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. It is crucial to ensure user permissions are enforced down through to the operating system. Protecting file permissions will ensure that if a nonprivileged user gains access to the system they will still not be able to access protected information from the cluster API, cluster configuration, and sensitive cluster information. This control relies on the underlying operating system also having been properly configured to allow only least privileged access to perform required operations. Satisfies: SRG-APP-000133-CTR-000300, SRG-APP-000133-CTR-000295, SRG-APP-000133-CTR-000305, SRG-APP-000133-CTR-000310

Check Content

File system permissions: 1. Ensure correct permissions of the files in /etc/rancher/rke2 cd /etc/rancher/rke2 ls -l all owners are root:root all permissions are 0600 2. Ensure correct permissions of the files in /var/lib/rancher/rke2 cd /var/lib/rancher/rke2 ls -l all owners are root:root 3. Ensure correct permissions of the files and directories in /var/lib/rancher/rke2/agent cd /var/lib/rancher/rke2/agent ls -l owners and group are root:root File permissions set to 0640 for the following: rke2controller.kubeconfig kubelet.kubeconfig kubeproxy.kubeconfig Certificate file permissions set to 0600 client-ca.crt client-kubelet.crt client-kube-proxy.crt client-rke2-controller.crt server-ca.crt serving-kubelet.crt Key file permissions set to 0600 client-kubelet.key serving-kubelet.key client-rke2-controller.key client-kube-proxy.key The directory permissions to 0700 pod-manifests etc 4. Ensure correct permissions of the files in /var/lib/rancher/rke2/bin cd /var/lib/rancher/rke2/bin ls -l all owners are root:root all files are 0750 5. Ensure correct permissions of the directory /var/lib/rancher/rke2/data cd /var/lib/rancher/rke2 ls -l all owners are root:root permissions are 0750 6. Ensure correct permissions of each file in /var/lib/rancher/rke2/data cd /var/lib/rancher/rke2/data ls -l all owners are root:root all files are 0640 7. Ensure correct permissions of /var/lib/rancher/rke2/server cd /var/lib/rancher/rke2/server ls -l all owners are root:root The following directories are set to 0700 cred db tls The following directories are set to 0750 manifests logs The following file is set to 0600 token 8. Ensure the RKE2 Server configuration file on all RKE2 Server hosts contain the following: (cat /etc/rancher/rke2/config.yaml) write-kubeconfig-mode: "0600" If any of the permissions specified above do not match the required level, this is a finding.

Fix Text

File system permissions: 1. Fix permissions of the files in /etc/rancher/rke2: cd /etc/rancher/rke2 chmod 0600 ./* chown root:root ./* ls -l 2. Fix permissions of the files in /var/lib/rancher/rke2: cd /var/lib/rancher/rke2 chown root:root ./* ls -l 3. Fix permissions of the files and directories in /var/lib/rancher/rke2/agent: cd /var/lib/rancher/rke2/agent chown root:root ./* chmod 0700 pod-manifests chmod 0700 etc find . -maxdepth 1 -type f -name "*.kubeconfig" -exec chmod 0640 {} \; find . -maxdepth 1 -type f -name "*.crt" -exec chmod 0600 {} \; find . -maxdepth 1 -type f -name "*.key" -exec chmod 0600 {} \; ls -l 4. Fix permissions of the files in /var/lib/rancher/rke2/bin: cd /var/lib/rancher/rke2/agent/bin chown root:root ./* chmod 0750 ./* ls -l 5. Fix permissions directory of /var/lib/rancher/rke2/data: cd /var/lib/rancher/rke2/agent chown root:root data chmod 0750 data ls -l 6. Fix permissions of files in /var/lib/rancher/rke2/data: cd /var/lib/rancher/rke2/data chown root:root ./* chmod 0640 ./* ls -l 7. Fix permissions in /var/lib/rancher/rke2/server: cd /var/lib/rancher/rke2/server chown root:root ./* chmod 0700 cred chmod 0700 db chmod 0700 tls chmod 0750 manifests chmod 0750 logs chmod 0600 token ls -l Edit the RKE2 Server configuration file on all RKE2 Server hosts, located at /etc/rancher/rke2/config.yaml, to contain the following: write-kubeconfig-mode: "0600" Once the configuration file is updated, restart the RKE2 Server. Run the command: systemctl restart rke2-server

Additional Identifiers

Rule ID: SV-254564r1016531_rule

Vulnerability ID: V-254564

Group Title: SRG-APP-000133-CTR-000300

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.