This document discusses using the ELK stack (Elasticsearch, Logstash, Kibana) for attack monitoring. It provides an overview of each component, describes how to set up ELK and configure Logstash for log collection and parsing. It also demonstrates log forwarding using Logstash Forwarder, and shows how to configure alerts and dashboards in Kibana for attack monitoring. Examples are given for parsing Apache logs and syslog using Grok filters in Logstash.