Abstract: A packet intrusion detection rule simplification apparatus and method and an intrusion detection apparatus and method are provided. Test conditions of at least one intrusion detection rules are rearranged based on test items, and the same test conditions for the same test items are grouped. Group rules having a connection structure of the test conditions are generated so that the test items and orders of the intrusion detection rules are satisfied. A common rule consisting of test conditions existing at the test start positions in the connection structure of the group rules is generated. Next, packet intrusion detection is performed by using the common rule, and the packet intrusion detection is performed by using the group rules. According, it is possible to reduce a load involved in the intrusion detection process by using the grouped and simplified intrusion detection rules.

Abstract: A method for dynamically changing an intrusion detection rule in a kernel level intrusion detection system is disclosed. The method includes the steps of: a) generating a replica of the intrusion detection rule in a kernel area; b) changing the replica of the intrusion detection rule according to a request of changing the intrusion detection rule from the kernel area; and c) changing a currently applied intrusion detection rule by exchanging a value of a pointer representing the intrusion detection rule with a value of a pointer representing the changed replica of the intrusion detection rule.