Session State Transition Based Large Network IDS

In order to present large-scale malicious attacks on an ISP network to maintain network services, we have designed a method to record key packets classified by sessions. Session is the service provided above the IP layer. We define a TCP connection a session, a UDP packet exchange a session, or echo and echo response of ICMP to be a session. The research of network attack/intrusion/information collection has shown that most of the illegal action performed would have something special ongoing in such sessions. For example, winnuke will send OOB packets to the 139 port of a host; most of the platform detection will use strange packets too. Not only the strange packets itself, but the sequence of such packets going through the network indicate the attack. For example, teardrop will transmit packets that have abnormal fragment offset in the second packet, then cause some platform to crash. Some patterns of sessions will be created by flood based attack/information collection. For example,...

• Type: Conference
• Year: 1999
• Where: RAID
• Authors: Qianli Zhang, Xing Li
• Keywords: Computer Networks, Key Packets, RAID 1999, Session States, Strange Packets