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This paper presents a comprehensive approach to detecting and tracking network intrusions, including the use of traffic-flow signatures, correlation of signatures, and map-based distributed intrusion tracking. The techniques outlined in this research paper aim to counter the devious techniques used by hackers and enhance network security.
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Towards trapping wily intruders in the large Glenn Mansfield, Kohei Ohta, Yohsuke Takei, Nei Kato, Yoshiaki Nemoto Cyber Solutions Inc., Tohoku University RAID’99, September 7-9, 1999
outline • background • network-based illegal access detection • characteristics of network intrusions • signatures of intrusions • detection of intrusion from traffic-flow • traffic-flow signature • correlation of signatures • experimental evaluation • map-based distributed intrusion tracking • conclusion
background • Network-based illegal access detection • rapid increase in network bandwidth • devious techniques (e.g. spoofing) used by the hackers.
Suspicious Behavior ? Repeated Failures ? Signatures ? Knocking at several doors
characteristics of network intrusions (I) • Signals from TCP-Reset Characteristics
characteristics of network intrusions (II) • Number of ICMP-UR packets (port SNMP(161))
characteristics of network intrusions (III) • ICMP destination port unreachable messages for SNMP port (under scan)
characteristics of network intrusions (IV) • Distribution of inter-message interval
detection of intrusion from traffic-flow signature • Packet contents may be encrypted • Packet contents may be manipulated • The traffic volume may be very large
correlating traffic-flow signature Correlation of traffic patterns: correlation coefficient r (A, B are two flows)
experimental evaluation(configuration) • 100Mbps FDDI backbone network • ICMP echo request/reply messages
relay of ICMP echo reply • A burst of ICMP echo reply triggered by broadcast ping, Smurf
relay of ICMP echo request • A cluster of ICMP echo request triggering the bursty ICMP reply
ChaIn: Charting the Internet http://www.cysols.com/IPAMaps/ IPA:Information technology Promotion Agency, Japan(www.ipa.go.jp)
inter-N/W communication I • Traffic monitoring at N/W border • watch all the traffic • process only suspicious packets. • Use network configuration information to trap and/or track-down the intruder. • Communication using SNMP(v3) notifications.
inter-N/W communication II http://…………. ftp://………….. snmp://……….. detection system detection system SNMP INFORM PDU http://…………. ftp://………….. snmp://………..
X AS3 AS1 AS2 X Intruder Saw this? Saw this? Saw this? 5. Network Security Using Maps Suspicious !! Suspicious !! Suspicious !! Suspicious !! AS1 AS2 Monitor AS0 X No Yes No No Yes
conclusion • Profiling network traffic to distinguish normal usage from abnormal or ill-intentioned usage. • Monitoring suspicious signals in a distributed information collection framework • A new technique based on packet flow monitoring to counter the threats posed by spoofing. • Use of network configuration information to track down intruders. • Use of SNMP based messaging system.