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Tatehiro Kaiwa, University of Aizu. E-mail:m5081224@u-aizu.ac.jp. Dynamics of Malicious Software in the Internet. 1. Outline. Random Network and Scale-free Network Observed Arrivals of E-mail Simulation Model of Worm Spread Dynamics Local Network Structure Inference
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Tatehiro Kaiwa, University of Aizu. E-mail:m5081224@u-aizu.ac.jp Dynamics of Malicious Softwarein the Internet 1
Outline • Random Network and Scale-free Network • Observed Arrivals of E-mail • Simulation Model of Worm Spread Dynamics • Local Network Structure Inference • Mathematical Model of Outbreak • Hub Defense Strategy • Conclusion 2
Two Model of Network • Model of Network • Random Network Degree Distribution: bell curve • Scale-free Network Degree Distribution: power-law 3
Scale-free and Preferential Attachment Scale-free Network is a network with power-law degree distribution. 4
Structure of E-mail Network *k: The number of links. Degree Distribution of an e-mail network. Reference: Holger Ebel, Lutz-Ingo Mielsch, and Stefan Bornholdt, “Scale-free topology of e-mail networks”, Physical Review E 66, 2002 5
Spoofed From-field • The From-filed of an e-mail message a worm sends is varies and/or is spoofed. • It is almost impossible to identify where a worm sends the e-mail and how many worms send observed e-mails. • It is only arrival intervals that we can obtain a correct data from received e-mails. 6
Observed Arrivals of E-mail • There are log data* of the time on which each e-mail messages with a worm attached arrived at University of Aizu. * http://web-int/labs/istc/ipc/Security/virus/index.html 7
Arrival Intervals of Simulation i) ii) iii) i) mk:115.619 ii) mk:92.15 iii) mk:61.95 *mk : Mean of Number of links neighbors have. 10
Hub Defense Strategy (1) Difference of Number of immune hub nodes. *h = Number of immune hub nodes 12
Hub Defense Strategy (2) Comparison Between Hub Defense and Random Defense r = Number of immune nodes selected randomly. h= Number of immune hub nodes. 13
Conclusion • Observing arrival intervals, we can estimate damage of a worm and estimate a network structure around observer. • We can confirm that hub defense strategy is an effective method in this network even though the number of immune hub nodes are not much enough. 14
Thank you 15