Biblio

Access control in the Internet of Things (IoT) often depends on a situation — for example, "the user is at home” — that can only be tracked using multiple devices. In contrast to the (well-studied) smartphone frameworks, enforcement of situational constraints in the IoT poses new challenges because access control is fundamentally decentralized. It takes place in multiple independent frameworks, subjects are often external to the enforcement system, and situation tracking requires cross-framework interaction and permissioning. Existing IoT frameworks entangle access-control enforcement and situation tracking. This results in overprivileged, redundant, inconsistent, and inflexible implementations. We design and implement a new approach to IoT access control. Our key innovation is to introduce "environmental situation oracles” (ESOs) as first-class objects in the IoT ecosystem. An ESO encapsulates the implementation of how a situation is sensed, inferred, or actuated. IoT access-control frameworks can use ESOs to enforce situational constraints, but ESOs and frameworks remain oblivious to each other's implementation details. A single ESO can be used by multiple access-control frameworks across the ecosystem. This reduces inefficiency, supports consistent enforcement of common policies, and — because ESOs encapsulate sensitive device-access rights — reduces overprivileging. ESOs can be deployed at any layer of the IoT software stack where access control is applied. We implemented prototype ESOs for the IoT resource layer, based on the IoTivity framework, and for the IoT Web services, based on the Passport middleware.

In mobile platforms and their app markets, controlling app permissions and preventing abuse of private information are crucial challenges. Information Flow Control (IFC) is a powerful approach for formalizing and answering user concerns such as: "Does this app send my geolocation to the Internet?" Yet despite intensive research efforts, IFC has not been widely adopted in mainstream programming practice. Abstract We observe that the typical structure of Android apps offers an opportunity for a novel and effective application of IFC. In Android, an app consists of a collection of a few dozen "components", each in charge of some high-level functionality. Most components do not require access to most resources. These components are a natural and effective granularity at which to apply IFC (as opposed to the typical process-level or language-level granularity). By assigning different permission labels to each component, and limiting information flow between components, it is possible to express and enforce IFC constraints. Yet nuances of the Android platform, such as its multitude of discretionary (and somewhat arcane) communication channels, raise challenges in defining and enforcing component boundaries. Abstract We build a system, DroidDisintegrator, which demonstrates the viability of component-level IFC for expressing and controlling app behavior. DroidDisintegrator uses dynamic analysis to generate IFC policies for Android apps, repackages apps to embed these policies, and enforces the policies at runtime. We evaluate DroidDisintegrator on dozens of apps.

We show that elliptic-curve cryptography implementations on mobile devices are vulnerable to electromagnetic and power side-channel attacks. We demonstrate full extraction of ECDSA secret signing keys from OpenSSL and CoreBitcoin running on iOS devices, and partial key leakage from OpenSSL running on Android and from iOS's CommonCrypto. These non-intrusive attacks use a simple magnetic probe placed in proximity to the device, or a power probe on the phone's USB cable. They use a bandwidth of merely a few hundred kHz, and can be performed cheaply using an audio card and an improvised magnetic probe.