摘要： 提出了多层次网络安全强审计模型BrosaAudit，并根据该模型设计并实现了相应的ACT-NetAudit 系统。和现有的网络安全审计系统相比，BrosaAudit 模型及审计系统能够从不同的层次对网络安全状况进行更全面的审计，为发现和追踪安全事件提供了更强有力的支持，有很强的实用性。

关键词: 网络安全；安全模型；安全审计

Abstract: The paper proposes an innovative multi-level model BrosaAudit for network security audit, designs and implements the ACT-NetAudit system according to the BrosaAudit model. Comparing to existing security audit systems, ACT-NetAudit can provide much more comprehensive,detailed, reliable and valuable audit information at different network layers for security administrators when network security related events happens,and play a great role in discovering and tracing malicious network activities. BrosaAudit model and ACT-NetAudit system have great practicability and flexibility.

Key words: Network security; Security model; Security audit