Biblio

Commercial networks today have diverse security policies, defined by factors such as the type of traffic they carry, nature of applications they support, access control objectives, organizational principles etc. Ideally, the wide diversity in SDN controller frameworks should prove helpful in correctly and efficiently enforcing these policies. However, this has not been the case so far. By requiring the administrators to implement both security as well as performance objectives in the SDN controller, these frameworks have made the task of security policy enforcement in SDNs a challenging one. We observe that by separating security policy enforcement from performance optimization, we can facilitate the use of SDN for flexible policy management. To this end, we propose Oreo, a transparent performance enhancement layer for SDNs. Oreo allows SDN controllers to focus entirely on a correct security policy enforcement, and transparently optimizes the dataplane thus defined, reducing path stretch, switch memory consumption etc. Optimizations are performed while guaranteeing that end-to-end reachability characteristics are preserved – meaning that the security policies defined by the controller are not violated. Oreo performs these optimizations by first constructing a network-wide model describing the behavior of all traffic, and then optimizing the paths observed in the model by solving a multi-objective optimization problem. Initial experiments suggest that the techniques used by Oreo is effective, fast, and can scale to commercial-sized networks.

Using stolen or weak credentials to bypass authentication is one of the top 10 network threats, as shown in recent studies. Disguising as legitimate users, attackers use stealthy techniques such as rootkits and covert channels to gain persistent access to a target system. However, such attacks are often detected after the system misuse stage, i.e., the attackers have already executed attack payloads such as: i) stealing secrets, ii) tampering with system services, and ii) disrupting the availability of production services.

In this talk, we analyze a real-world credential stealing attack observed at the National Center for Supercomputing Applications. We show the disadvantages of traditional detection techniques such as signature-based and anomaly-based detection for such attacks. Our approach is a complement to existing detection techniques. We investigate the use of Probabilistic Graphical Model, specifically Factor Graphs, to integrate security logs from multiple sources for a more accurate detection. Finally, we propose a security testbed architecture to: i) simulate variants of known attacks that may happen in the future, ii) replay such attack variants in an isolated environment, and iii) collect and share security logs of such replays for the security research community.

Modern industrial control systems (ICSes) are increasingly adopting Internet technology to boost control efficiency, which unfortunately opens up a new frontier for cyber-security. People have typically applied existing Internet security techniques, such as firewalls, or anti-virus or anti-spyware software. However, those security solutions can only provide fine-grained protection at single devices. To address this, we design a novel software-defined networking (SDN) architecture that offers the global visibility of a control network infrastructure, and we investigate innovative SDN-based applications with the focus of ICS security, such as network verification and self-healing phasor measurement unit (PMU) networks. We are also conducting rigorous evaluation using the IIT campus microgrid as well as a high-fidelity testbed combining network emulation and power system simulation.

Modern industrial control systems (ICSes) are increasingly adopting Internet technology to boost control efficiency, which unfortunately opens up a new frontier for cyber-security. People have typically applied existing Internet security techniques, such as firewalls, or anti-virus or anti-spyware software. However, those security solutions can only provide fine-grained protection at single devices. To address this, we design a novel software-defined networking (SDN) architecture that offers the global visibility of a control network infrastructure, and we investigate innovative SDN-based applications with the focus of ICS security, such as network verification and self-healing phasor measurement unit (PMU) networks. We are also conducting rigorous evaluation using the IIT campus microgrid as well as a high-fidelity testbed combining network emulation and power system simulation.

Maintaining the security and privacy hygiene of mobile apps is a critical challenge. Unfortunately, no program analysis algorithm can determine that an application is “secure” or “malware-free.” For example, if an application records audio during a phone call, it may be malware. However, the user may want to use such an application to record phone calls for archival and benign purposes. A key challenge for automated program analysis tools is determining whether or not that behavior is actually desired by the user (i.e., user expectation). This talk presents recent research progress in exploring user expectations in mobile app security.

Recent attacks show that threats to cyber infrastructure are not only increasing in volume, but are getting more sophisticated. The attacks may comprise multiple actions that are hard to differentiate from benign activity, and therefore common detection techniques have to deal with high false positive rates. Because of the imperfect performance of automated detection techniques, responses to such attacks are highly dependent on human-driven decision-making processes. While game theory has been applied to many problems that require rational decisionmaking, we find limitation on applying such method on security games. In this work, we propose Q-Learning to react automatically to the adversarial behavior of a suspicious user to secure the system. This work compares variations of Q-Learning with a traditional stochastic game. Simulation results show the possibility of Naive Q-Learning, despite restricted information on opponents.

This paper presents a framework for (1) generating variants of known attacks, (2) replaying attack variants in an isolated environment and, (3) validating detection capabilities of attack detection techniques against the variants. Our framework facilitates reproducible security experiments. We generated 648 variants of three real-world attacks (observed at the National Center for Supercomputing Applications at the University of Illinois). Our experiment showed the value of generating attack variants by quantifying the detection capabilities of three detection methods: a signature-based detection technique, an anomaly-based detection technique, and a probabilistic graphical model-based technique.

Today's cyber-physical systems (CPSs) can have very different characteristics in terms of control algorithms, configurations, underlying infrastructure, communication protocols, and real-time requirements. Despite these variations, they all face the threat of malicious attacks that exploit the vulnerabilities in the cyber domain as footholds to introduce safety violations in the physical processes. In this paper, we focus on a class of attacks that impact the physical processes without introducing anomalies in the cyber domain. We present the common challenges in detecting this type of attacks in the contexts of two very different CPSs (i.e., power grids and surgical robots). In addition, we present a general principle for detecting such cyber-physical attacks, which combine the knowledge of both cyber and physical domains to estimate the adverse consequences of malicious activities in a timely manner.

The successful operations of modern power grids are highly dependent on a reliable and ecient underlying communication network. Researchers and utilities have started to explore the opportunities and challenges of applying the emerging software-de ned networking (SDN) technology to enhance eciency and resilience of the Smart Grid. This trend calls for a simulation-based platform that provides sufcient exibility and controllability for evaluating network application designs, and facilitating the transitions from inhouse research ideas to real productions. In this paper, we present DSSnet, a hybrid testing platform that combines a power distribution system simulator with an SDN emulator to support high delity analysis of communication network applications and their impacts on the power systems. Our contributions lay in the design of a virtual time system with the tight controllability on the execution of the emulation system, i.e., pausing and resuming any speci ed container processes in the perception of their own virtual clocks, with little overhead scaling to 500 emulated hosts with an average of 70 ms overhead; and also lay in the ecient synchronization of the two sub-systems based on the virtual time. We evaluate the system performance of DSSnet, and also demonstrate the usability through a case study by evaluating a load shifting algorithm.

In recent years, online programming and software engineering education via information technology has gained a lot of popularity. Typically, popular courses often have hundreds or thousands of students but only a few course sta members. Tool automation is needed to maintain the quality of education. In this paper, we envision that the capability of quantifying behavioral similarity between programs is helpful for teaching and learning programming and software engineering, and propose three metrics that approximate the computation of behavioral similarity. Speci cally, we leverage random testing and dynamic symbolic execution (DSE) to generate test inputs, and run programs on these test inputs to compute metric values of the behavioral similarity. We evaluate our metrics on three real-world data sets from the Pex4Fun platform (which so far has accumulated more than 1.7 million game-play interactions). The results show that our metrics provide highly accurate approximation to the behavioral similarity. We also demonstrate a number of practical applications of our metrics including hint generation, progress indication, and automatic grading.

While there have been various studies identifying and classifying Android malware, there is limited discussion of the broader class of apps that fall in a gray area. Mobile grayware is distinct from PC grayware due to differences in operating system properties. Due to mobile grayware’s subjective nature, it is difficult to identify mobile grayware via program analysis alone. Instead, we hypothesize enhancing analysis with text analytics can effectively reduce human effort when triaging grayware. In this paper, we design and implement heuristics for seven main categories of grayware.We then use these heuristics to simulate grayware triage on a large set of apps from Google Play. We then present the results of our empirical study, demonstrating a clear problem of grayware. In doing so, we show how even relatively simple heuristics can quickly triage apps that take advantage of users in an undesirable way.
 

In this paper we explore the differential perceptions of cybersecurity professionals and general users regarding access rules and passwords. We conducted a preliminary survey involving 28 participants: 15 cybersecurity professionasl and 13 general users. We present our preliminary findings and explain how such survey data might be used to improve security in practice. We focus on user fatigue with access rules and passwords.

Anonymous messaging platforms like Whisper and Yik Yak allow users to spread messages over a network (e.g., a social network) without revealing message authorship to other users. The spread of messages on these platforms can be modeled by a diffusion process over a graph. Recent advances in network analysis have revealed that such diffusion processes are vulnerable to author deanonymization by adversaries with access to metadata, such as timing information. In this work, we ask the fundamental question of how to propagate anonymous messages over a graph to make it difficult for adversaries to infer the source. In particular, we study the performance of a message propagation protocol called adaptive diffusion introduced in (Fanti et al., 2015). We prove that when the adversary has access to metadata at a fraction of corrupted graph nodes, adaptive diffusion achieves asymptotically optimal source-hiding and significantly outperforms standard diffusion. We further demonstrate empirically that adaptive diffusion hides the source effectively on real social networks.
 

Anonymous messaging applications have recently gained popularity as a means for sharing opinions without fear of judgment or repercussion. These messages propagate anonymously over a network, typically de ned by social connections or physical proximity. However, recent advances in rumor source detection show that the source of such an anonymous message can be inferred by certain statistical inference attacks. Adaptive di usion was recently proposed as a solution that achieves optimal source obfuscation over regular trees. However, in real social networks, the degrees difer from node to node, and adaptive di usion can be signicantly sub-optimal. This gap increases as the degrees become more irregular.

In order to quantify this gap, we model the underlying network as coming from standard branching processes with i.i.d. degree distributions. Building upon the analysis techniques from branching processes, we give an analytical characterization of the dependence of the probability of detection achieved by adaptive di usion on the degree distribution. Further, this analysis provides a key insight: passing a rumor to a friend who has many friends makes the source more ambiguous. This leads to a new family of protocols that we call Preferential Attachment Adaptive Di usion (PAAD). When messages are propagated according to PAAD, we give both the MAP estimator for nding the source and also an analysis of the probability of detection achieved by this adversary. The analytical results are not directly comparable, since the adversary's observed information has a di erent distribution under adaptive di usion than under PAAD. Instead, we present results from numerical experiments that suggest that PAAD achieves a lower probability of detection, at the cost of increased communication for coordination.

In this paper, we develop a new framework to analyze stability and stabilizability of Linear Switched Systems (LSS) as well as their gain computations. Our approach is based on a combination of state space operator descriptions and the Youla parametrization and provides a unified way for analysis and synthesis of LSS, and in fact of Linear Time Varying (LTV) systems, in any lp induced norm sense. By specializing to the l∞ case, we show how Linear Programming (LP) can be used to test stability, stabilizability and to synthesize stabilizing controllers that guarantee a near optimal closed-loop gain.