Enable WAF with Modsecurity from Ingress Nginx

Enable WAF with Modsecurity from Ingress Nginx

Export modsecurity.conf from ingress nginx controller

POD_NAME=$(kubectl get pods --namespace ingress-nginx -l "app.kubernetes.io/component=controller,app.kubernetes.io/name=ingress-nginx" -o jsonpath="{.items[0].metadata.name}")

kubectl exec -it $POD_NAME -n ingress-nginx -- cat /etc/nginx/modsecurity/modsecurity.conf > modsecurity.conf

Change configuration to support JSON and serial log

# SecAuditLogType Concurrent
# SecAuditLog /var/log/modsec_audit.log

SecAuditLogType Serial
SecAuditLog /dev/stdout
SecAuditLogFormat JSON

Create a configmap to use customized modsecurity.conf settings

kubectl create configmap modsecurity --from-file=modsecurity.conf=modsecurity.conf -n=ingress-nginx

Update ingress nginx helm values

  ## Additional volumeMounts to the controller main container.
    - name: modsecurity
      mountPath: /etc/nginx/modsecurity/modsecurity.conf
      subPath: modsecurity.conf
      readOnly: true

  ## Additional volumes to the controller pod.
    - name: modsecurity
        name: modsecurity

helm upgrade <name> ingress-nginx/ingress-nginx -n ingress-nginx -f nginx_values.yaml

Create nginx ingress object and annotate it in below

    nginx.ingress.kubernetes.io/enable-modsecurity: "true"
    nginx.ingress.kubernetes.io/enable-owasp-core-rules: "true"
    nginx.ingress.kubernetes.io/modsecurity-snippet: |
      # SecRuleEngine Off|On|DetectionOnly
      SecRuleEngine On
      SecRuleRemoveById 920350


Here are some commands to test modsecurity WAF protection

curl -X POST YOUR_URL -F "user='<script><alert>Hello></alert></script>'"
curl -X POST YOUR_URL -F "user='AND 1=1;"