Jean-Pierre Seifert

A cellular network is a closed system, and each network operator has built a unique ‘walled garden’ for their network by combining different operation policies, network configurations, and implementation optimizations. Unfortunately, some of these combinations can induce performance degradation due to misconfiguration or unnecessary procedures. To detect such degradation, a thorough understanding of even the minor details of the standards and operator-specific implementations is important. However, it is difficult to detect such problems, as the control plane is complicated by numerous procedures. This paper introduces a simple yet powerful method that diagnoses these problems by exploiting the operator-specific implementations of cellular networks. We develop a signaling collection and analysis tool that collects control plane messages from operators and finds problems through comparative analysis. The analysis process consists of three different control plane comparison procedures that can find such problems effectively. These individual procedures use a time threshold, control flow sequence, and signaling failure as the basis for comparison. To this end, we collect approximately 3.1 million control plane messages from 13 major cellular operators worldwide. As a case study, we analyze the circuit-switched fallback technology that triggers generation crossover between third generation and long-term evolution technologies.

Securing Computer Systems against all kind of threats is an impossible challenge to fulfill. Although, in the field of Legal Metrology, it shall be assured that one can rely on the measurement carried out by a trusted computer system. In a distributed environment, a measurement instrument cannot be simply disconnected to gurantee its security. However, being able to monitor the computer systems constantly in order to deduce a normal system behaviour, can be a particular promising approach to secure such systems. In cases of detected anomalies, the system evaluates them to measure the severity of the detected incident and place it into three different categories: green, yellow and red. The presented Anomaly Detection Module can detect attacks against distributed applications in an cloud computing environment, using pattern recognition for clustering as well as statistical approaches. Both, inexperienced and experienced attacks have been tested and results are presented.

Embedded systems show the tendency of becoming more and more connected. This fact combined with the trend towards the Internet of Things, from which measuring instruments are not immune (e.g., smart meters), lets one assume that security in measuring instruments will inevitably play an important role soon. Additionally, measuring instruments have adopted general-purpose operating systems to offer the user a broader functionality that is not necessarily restricted towards measurement alone. In this paper, a flexible software system architecture is presented that addresses these challenges within the framework of essential requirements laid down in the Measuring Instruments Directive of the European Union. This system architecture tries to eliminate the risks general-purpose operating systems have by wrapping them, together with dedicated applications, in secure sandboxes, while supervising the communication between the essential parts and the outside world.

With Firefox OS, Mozilla is making a serious push for an HTML5-based mobile platform. In order to assuage security concerns over providing hardware access to web applications, Mozilla has introduced a number of mechanisms that make the security landscape of Firefox OS distinct from both the desktop web and other mobile operating systems. From an application security perspective, the two most significant of these mechanisms are the the introduction of a default Content Security Policy and code review in the market. This paper describes how lightweight static analysis can augment these mechanisms to find vulnerabilities which have otherwise been missed. We provide examples of privileged applications in the market that contain vulnerabilities that can be automatically detected. In addition to these findings, we show some of the challenges that occur when desktop software is repurposed for a mobile operating system. In particular, we argue that the caching of certificate overrides across applications--a known problem in Firefox OS--generates a counter-intuitive user experience that detracts from the security of the system.