With a huge amount of personal information ripe for the taking in modern Online Social Networks (OSNs), privacy breaches have become a central concern, especially with an introduction of automated attacks by socialbots, which can automatically extract victims' private content by exploiting social behavior to befriend them. In this talk, we explore the social strategies of socialbots and see how they can harvest the most of private information using at most k friend requests, modeled as Max-Crawling. The two main challenges of this problem are how to cope with incomplete knowledge of network topology and how to model users' responses to friend requests. Accordingly, we present an adaptive approximation algorithm using adaptive stochastic optimization. The key feature of our solution lies in the adaptive method, where partial network topology is revealed after each successful friend request. Thus the decision of whom to send a friend request to next is made with the outcomes of past decisions taken into account. Traditional tools break down when attempting to place a bound on the performance of this technique with realistic user models as it is no longer submodular. Therefore, we additionally introduce a novel curvature-based technique to construct an approximation ratio of for a model of user behavior learned from empirical measurements on Facebook.

Dr. My T. Thai received her Ph.D. degree in computer science from the University of Minnesota, in 2005. She is currently a full Professor and Associate Chair for Research at the Department of Computer and Information Science and Engineering, University of Florida. Her current research interests include algorithms and optimization on network science and engineering, with a focus on privacy and security in billion-scale networks. She was a recipient of several research awards, including a UF Provosts Excellence Award for Assistant Professors, UFRF Professorship, a DoD YIP, and an NSF CAREER Award. She has engaged in many professional activities, such as being the PC Chair of a number of IEEE conferences. She is the Founding Editor-in-Chief of Computational Social Networks, an Associate Editor of JOCO, the IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS, the IEEE TRANSACTIONS ON NETWORK SCIENCE, and a Series Editor of SpringerBriefs in Optimization.