In order to resolve huge amount of anomaly
information generated by Intrusion Detection System (IDS), this paper presents and evaluates a log analysis system for IDS based on Cloud Computing technique,
named IDS Cloud Analysis System (ICAS). To achieve this, there are two basic components have to be designed. First is the regular parser, which normalizes
the raw log files. The other is the Analysis Procedure, which contains Data Mapper and Data Reducer. The Data Mapper is designed to anatomize alert messages and the Data Reducer is used to aggregates and merges. As a result, this paper will show that the
performance of ICAS is suitable for analyzing and reducing large alerts.