Kehuan Zhang

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We explore the threat of smartphone malware with access to on-board sensors, which opens new avenues for illicit collection of private information. While existing work shows that such “sensory malware” can convey raw sensor data (e.g., video and audio) to a remote server, these approaches lack stealthiness, incur significant communication and computation(More)
With software-as-a-service becoming mainstream, more and more applications are delivered to the client through the Web. Unlike a desktop application, a web application is split into browser-side and server-side components. A subset of the application’s internal information flows are inevitably exposed on the network. We show that despite encryption,(More)
The emergence of cost-effective cloud services offers organizations great opportunity to reduce their cost and increase productivity. This development, however, is hampered by privacy concerns: a significant amount of organizational computing workload at least partially involves sensitive data and therefore cannot be directly outsourced to the public cloud.(More)
One rising trend in today's consumer electronics is the wearable devices, e.g., smartwatches. With tens of millions of smartwatches shipped, however, the security implications of such devices are not fully understood. Although previous studies have pointed out some privacy concerns about the data that can be collected, like personalized health information,(More)
With the Internet becoming the dominant channel for marketing and promotion, online advertisements are also increasingly used for illegal purposes such as propagating malware, scamming, click frauds, etc. To understand the gravity of these malicious advertising activities, which we call <i>malvertising</i>, we perform a large-scale study through analyzing(More)
A web application is a "two-part" program, with its components deployed both in the browser and in the web server. The communication between these two components inevitably leaks out the program's internal states to those eavesdropping on its web traffic, simply through the side channel features of the communication such as packet length and timing, even if(More)
A multi-user system usually involves a large amount of information shared among its users. The security implications of such information can never be underestimated. In this paper, we present a new attack that allows a malicious user to eavesdrop on other users’ keystrokes using such information. Our attack takes advantage of the stack information of a(More)
The specifications of an application's security configuration are crucial for understanding its security policies, which can be very helpful in security-related contexts such as misconfiguration detection. Such specifications, however, are often ill-documented, or even close because of the increasing use of graphic user interfaces to set program options. In(More)
Many new specialized hardware components have been integrated into Android smartphones to improve mobility and usability, such as touchscreen, Bluetooth module, and NFC controller. At the system level, the kernel of Android is built on Linux and inherits its device management mechanisms. However, the security implications surfaced from the integration of(More)
The popularity of mobile devices has made people's lives more convenient, but threatened people's privacy at the same time. As end users are becoming more and more concerned on the protection of their private information, it is even harder for hackers to track a specific user by using conventional technologies. For example, cookies might be cleared by users(More)