Abstract: Intrusion detection is a common network security technology, cloud computing proposes new requirements to intrusion detection system(IDS). In distributed intrusion detection system, there are many different types of IDSs, and data fusion enables the combination of the output of different types of IDSs. The design and achievement of data fusion process model are discussed. By making inferences from the combined data, a multiple level-of-abstraction situational description is emerged, and an analysis of the threat of the current situation is presented.

Key words: cloud computing, distributed intrusion detection system, data fusion, situational description