Risiken

Die Audit-Protokollierung ist ein wichtiger Aspekt der Kubernetes-Sicherheit und des Betriebsmanagements. Sie liefert eine detaillierte Aufzeichnung aller an den Kubernetes-API-Server gerichteten Anfragen und ermöglicht es Administratoren, Aktionen zu überwachen und nachzuverfolgen, Sicherheitsverletzungen zu erkennen und gesetzliche Vorschriften einzuhalten. Die Entwicklung umfassender Audit-Protokollrichtlinien stellt sicher, dass kritische Ereignisse erfasst und effektiv aufbewahrt werden.

Wichtige Überlegungen für Audit-Log-Richtlinien

1. Scope: Definieren Sie den Umfang der Audit-Protokollierung, einschließlich der zu erfassenden Ereignisse und der Granularität der Protokolle.
2. Retention: Bestimmen Sie, wie lange Audit-Protokolle je nach organisatorischen und gesetzlichen Anforderungen aufbewahrt werden sollen.
3. Storage: Legen Sie fest, wo die Prüfprotokolle gespeichert werden sollen, und sorgen Sie dafür, dass sie sicher und zugänglich sind.
4. Access Control: Implementieren Sie Zugriffskontrollen, um sicherzustellen, dass nur autorisiertes Personal auf Audit-logs zugreifen und diese verwalten kann.
5. Monitoring and Alerting: Einrichtung von Überwachungs- und Warnsystemen für kritische Ereignisse, die in den Audit-Protokollen erfasst werden.

Setting Up Audit Logging in Kubernetes

1. Enable Audit Logging

To enable audit logging, you need to configure the Kubernetes API server with the appropriate audit policy file and log file path.

1. Create an Audit Policy File

An audit policy file defines which events are logged and at what level. Below is an example audit policy:

apiVersion: audit.k8s.io/v1
kind: Policy
rules:
- level: Metadata
  resources:
  - group: ""
    resources: ["pods", "services", "namespaces"]
- level: Request
  users: ["admin"]
  verbs: ["create", "update", "patch", "delete"]
- level: None
  users: ["system:serviceaccount:kube-system:default"]
  verbs: ["get", "list", "watch"]
- level: RequestResponse
  resources:
  - group: ""
    resources: ["secrets"]
  omitStages:
  - "RequestReceived"

2. Configure the API Server

Update the API server configuration to use the audit policy file and specify the log file path.

--audit-policy-file=/etc/kubernetes/audit-policy.yaml --audit-log-path=/var/log/kubernetes/audit.log --audit-log-maxage=30 --audit-log-maxbackup=10 --audit-log-maxsize=100

3. Deploy the Configuration

Ensure the audit policy file is placed in the specified directory and restart the API server to apply the configuration.

systemctl daemon-reload && systemctl restart kubelet

2. Define Retention Policies

Determine how long audit logs should be retained. This is typically based on regulatory requirements and organizational policies.

1. Set Retention Parameters

Configure the API server with retention parameters to manage log file rotation and retention.

--audit-log-maxage=30 --audit-log-maxbackup=10 --audit-log-maxsize=100

2. Archiving and Backup

Implement archiving and backup solutions to store audit logs for long-term retention. Use tools like AWS S3, Google Cloud Storage, or on-premise storage solutions.

# Example: Using a cron job to move logs to a backup location 0 0 * * * mv /var/log/kubernetes/audit.log /backup/location/audit-$(date +\%F).log

3. Secure Storage and Access Control

Ensure audit logs are stored securely and access is restricted to authorized personnel only.

1. Secure Storage

Store audit logs in a secure location with appropriate permissions.

chmod 600 /var/log/kubernetes/audit.log

2. Access Control

Use RBAC policies to control who can view and manage audit logs.

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: kube-system
  name: audit-log-reader
rules:
- apiGroups: [""]
  resources: ["pods/log"]
  verbs: ["get", "list"]

3. RoleBinding

Bind the role to a user or group.

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: read-audit-logs
  namespace: kube-system
subjects:
- kind: User
  name: audit-user
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: audit-log-reader
  apiGroup: rbac.authorization.k8s.io

4. Monitoring and Alerting

Set up monitoring and alerting for critical events captured in the audit logs.

1. Integrate with Logging Systems

Integrate audit logs with centralized logging systems like ELK Stack (Elasticsearch, Logstash, Kibana), Splunk, or Grafana.

# Example: Sending logs to Elasticsearch
filebeat.inputs:
- type: log
  paths:
    - /var/log/kubernetes/audit.log
output.elasticsearch:
  hosts: ["http://elasticsearch:9200"]
  index: "k8s-audit-logs-%{+yyyy.MM.dd}"

2. Configure Alerts

Set up alerts for specific events using monitoring tools.

# Example: Alerting configuration in Prometheus
groups:
- name: KubernetesAuditLogs
  rules:
  - alert: HighPrivilegeAction
    expr: rate(kube_audit_event_count{verb="create", resource="secrets"}[1m]) > 1
    for: 5m
    labels:
      severity: critical
    annotations:
      summary: "High privilege action detected"
      description: "High privilege action ({{ $labels.verb }}) detected on resource {{ $labels.resource }} by user {{ $labels.user }}."

Example Audit Policy File

apiVersion: audit.k8s.io/v1
kind: Policy
rules:
- level: Metadata
  resources:
  - group: ""
    resources: ["pods", "services", "namespaces"]
- level: Request
  users: ["admin"]
  verbs: ["create", "update", "patch", "delete"]
- level: None
  users: ["system:serviceaccount:kube-system:default"]
  verbs: ["get", "list", "watch"]
- level: RequestResponse
  resources:
  - group: ""
    resources: ["secrets"]
  omitStages:
  - "RequestReceived"

Conclusion

Developing comprehensive audit log policies in Kubernetes is essential for security, compliance, and operational transparency. By enabling audit logging, defining retention policies, securing log storage, implementing access controls, and setting up monitoring and alerting, organizations can effectively manage and utilize audit logs to enhance their Kubernetes cluster's security and performance. Regularly reviewing and updating these policies ensures they remain aligned with organizational needs and regulatory requirements.