arXiv subjects

Georg Carle

Publications and source records attributed to Georg Carle.

76 records · Page 5Linked to original sources

arXiv2016

Analyzing Locality of Mobile Messaging Traffic using the MATAdOR Framework

Mobile messaging services have gained a large share in global telecommunications. Unlike conventional services like phone calls, text messages or email, they do not feature a standardized environment enabling a federated and potentially local service architecture. We present an extensive and large-scale analysis of communication patterns for four popular mobile messaging services between 28 countries and analyze the locality of communication and the resulting impact on user privacy. We show that server architectures for mobile messaging services are highly centralized in single countries. This forces messages to drastically deviate from a direct communication path, enabling hosting and transfer countries to potentially intercept and censor traffic. To conduct this work, we developed a measurement framework to analyze traffic of such mobile messaging services. It allows to conduct automated experiments with mobile messaging applications, is transparent to those applications and does not require any modifications to the applications.

cs.NI↗

arXiv2016

GPLMT: A Lightweight Experimentation and Testbed Management Framework

Conducting experiments in federated, distributed, and heterogeneous testbeds is a challenging task for researchers. Researchers have to take care of the whole experiment life cycle, ensure the reproducibility of each run, and the comparability of the results. We present GPLMT, a flexible and lightweight framework for managing testbeds and the experiment life cycle. \gplmt provides an intuitive way to formalize experiments. The resulting experiment description is portable across varying experimentation platforms. GPLMT enables researchers to manage and control networked testbeds and resources, and conduct experiments on large-scale, heterogeneous, and distributed testbeds. We state the requirements and the design of GPLMT, describe the challenges of developing and using such a tool, and present selected user studies along with their experience of using GPLMT in varying scenarios.

cs.NI↗

arXiv2015

The Abandoned Side of the Internet: Hijacking Internet Resources When Domain Names Expire

The vulnerability of the Internet has been demonstrated by prominent IP prefix hijacking events. Major outages such as the China Telecom incident in 2010 stimulate speculations about malicious intentions behind such anomalies. Surprisingly, almost all discussions in the current literature assume that hijacking incidents are enabled by the lack of security mechanisms in the inter-domain routing protocol BGP. In this paper, we discuss an attacker model that accounts for the hijacking of network ownership information stored in Regional Internet Registry (RIR) databases. We show that such threats emerge from abandoned Internet resources (e.g., IP address blocks, AS numbers). When DNS names expire, attackers gain the opportunity to take resource ownership by re-registering domain names that are referenced by corresponding RIR database objects. We argue that this kind of attack is more attractive than conventional hijacking, since the attacker can act in full anonymity on behalf of a victim. Despite corresponding incidents have been observed in the past, current detection techniques are not qualified to deal with these attacks. We show that they are feasible with very little effort, and analyze the risk potential of abandoned Internet resources for the European service region: our findings reveal that currently 73 /24 IP prefixes and 7 ASes are vulnerable to be stealthily abused. We discuss countermeasures and outline research directions towards preventive solutions.

cs.NI↗

arXiv2014

Directed Security Policies: A Stateful Network Implementation

Large systems are commonly internetworked. A security policy describes the communication relationship between the networked entities. The security policy defines rules, for example that A can connect to B, which results in a directed graph. However, this policy is often implemented in the network, for example by firewalls, such that A can establish a connection to B and all packets belonging to established connections are allowed. This stateful implementation is usually required for the network's functionality, but it introduces the backflow from B to A, which might contradict the security policy. We derive compliance criteria for a policy and its stateful implementation. In particular, we provide a criterion to verify the lack of side effects in linear time. Algorithms to automatically construct a stateful implementation of security policy rules are presented, which narrows the gap between formalization and real-world implementation. The solution scales to large networks, which is confirmed by a large real-world case study. Its correctness is guaranteed by the Isabelle/HOL theorem prover.

cs.CR↗