The impact of hesitation on passive worm spreading in P2P networks

Abstract

P2P file-sharing networks allow peers (computers) to download files and make them available to other users on the network. The fear of downloading worm file is a reasonable reason to discourage users to utilize P2P file-sharing networks. So, peers may hesitate to open the downloaded files due to the concern of receiving poisoned files or being compromised by malwares. In this article, we present a model of spread of passive worm in P2P file-sharing networks, where susceptible peers which were already infected before, are reluctant to open new downloaded files. Here, we address this issue by introducing a modified SEIS model, where λe (average rate at which exposed peer opens a downloaded file) decreases with the number of reinfections n for a maximum of l times (λe(n+1) = 𝜖λe(n)where 0<𝜖<1represents the hesitation value). Hence, for a susceptible peer which was already infected by the worm, the hesitation to open a new downloaded file is quantified by the two parameters (𝜖,l). We studied numerically the effects of various system parameters on the time evolution of the peer states. At steady state and for every value of l, there exists a critical value 𝜖c below which the system is infection-free. A phase diagram in the plane (𝜖,l) is constructed that shows which phases are present according to the state variables. In addition, we introduced and evaluated the effect of different patch-based immunization strategies to show how they could block the spread of the worm in the system. The immunization patch is launched in the network at a time tl and will be out of order at a time tf (i.e. outdated patch). We found that the parameters (tl,tf, 𝜖) are very important to be defined when developing the immunization patch.