The Eavesdropper\u27s Dilemma

This paper examines the problem of surreptitious Internet interception from the eavesdropper\u27s point of view. We introduce the notion of fidelity in digital eavesdropping. In particular, we formalize several kinds of network noise that might degrade fidelity, most notably confusion, and show that reliable network interception may not be as simple as previously thought or even always possible. Finally, we suggest requirements for high fidelity network interception, and show how systems that do not meet these requirements can be vulnerable to countermeasures, which in some cases can be performed entirely by a third party without the cooperation or even knowledge of the communicating parties

On the Reliability of Current Generation Network Eavesdropping Tools

This paper analyzes the problem of interception of Internet traffic from the eavesdropper\u27s point of view. We examine the reliability and accuracy of transcripts, and show that obtaining high fidelity transcripts is harder than previously assumed. Even in highly favorable situations, such as capturing unencrypted traffic using standard protocols, simple -- and entirely unilateral -- countermeasures are shown to be sufficient to prevent accurate traffic analysis in many Internet interception configurations. In particular, these countermeasures were successful against every available eavesdropping system we tested. Central to our approach is a new class of techniques that we call confusion, which, unlike cryptography or steganography, does not require cooperation by the communicating parties and, in some case, can be employed entirely by a third party not involved in the communication at all

Security Protocols With Isotropic Channels

We investigate the security properties of isotropic channels, broadcast media in which a receiver cannot reliably determine whether a message originated from any particular sender and a sender cannot reliably direct a message away from any particular receiver. We show that perfect isotropism implies perfect (information-theoretic) secrecy, and that asymptotically close to perfect secrecy can be achieved on any channel that provides some (bounded) uncertainty as to sender identity. We give isotropic security protocols under both passive and active adversary models, and discuss the practicality of realizing isotropic channels over various media

Security Weaknesses in the APCO Project 25 Two-Way Radio System

APCO Project 25 (“P25”) is a suite of wireless communications protocols designed for public safety two-way (voice) radio systems. The protocols include security options in which voice and data traffic can be cryptographically protected from eavesdropping. This report analyzes the security of P25 systems against passive and active attacks. We find a number of protocol, implementation, and user interface weaknesses that can leak information to a passive eavesdropper and that facilitate active attacks. In particular, P25 systems are highly susceptible to active traffic analysis attacks, in which radio user locations are surreptitiously determined, and selective jamming attacks, in which an attacker can jam specific kinds of traffic (such as encrypted messages or key management traffic). The P25 protocols make such attacks not only feasible but highly efficient, requiring, for example, significantly less aggregate energy output from a jammer than from the legitimate transmitters

Sensor Network Security: More Interesting Than You Think

With the advent of low-power wireless sensor networks, a wealth of new applications at the interface of the real and digital worlds is emerging. A distributed computing platform that can measure properties of the real world, formulate intelligent inferences, and instrument responses, requires strong foundations in distributed computing, artificial intelligence, databases, control theory, and security. Before these intelligent systems can be deployed in critical infrastructures such as emergency rooms and powerplants, the security properties of sensors must be fully understood. Existing wisdom has been to apply the traditional security models and techniques to sensor networks. However, sensor networks are not traditional computing devices, and as a result, existing security models and methods are ill suited. In this position paper, we take the first steps towards producing a comprehensive security model that is tailored for sensor networks. Incorporating work from Internet security, ubiquitous computing, and distributed systems, we outline security properties that must be considered when designing a secure sensor network. We propose challenges for sensor networks – security obstacles that, when overcome, will move us closer to decreasing the divide between computers and the physical world

A³: An Extensible Platform for Application-Aware Anonymity

This paper presents the design and implementation of Application-Aware Anonymity (A³), an extensible platform for deploying anonymity-based services on the Internet. A³ allows applications to tailor their anonymity properties and performance characteristics according to specific communication requirements. To support flexible path construction, A³ exposes a declarative language (A³LOG) that enables applications to compactly specify path selection and instantiation policies executed by a declarative networking engine. We demonstrate that our declarative language is sufficiently expressive to encode novel multi-metric performance constraints as well as existing relay selection algorithms employed by Tor and other anonymity systems, using only a few lines of concise code. We experimentally evaluate the A³ system using a combination of trace-driven simulations and deployment on Planet- Lab. Our experimental results demonstrate that A3 can flexibly support a wide range of path selection and instantiation strategies at low performance overhead

Risking Communications Security: Potential Hazards of the Protect America Act

A new US law allows warrantless wiretapping whenever one end of the communication is believed to be outside national borders. This creates serious security risks: danger of exploitation of the system by unauthorized users, danger of criminal misuse by trusted insiders, and danger of misuse by government agents

On the reliability of current generation network eavesdropping tools

This paper analyzes the problem of interception of Internet traffic from the eavesdropper’s point of view. We examine the reliability and accuracy of transcripts, and show that obtaining “high fidelity ” transcripts is harder than previously assumed. Even in highly favorable situations, such as capturing unencrypted traffic using standard protocols, simple – and entirely unilateral – countermeasures are shown to be sufficient to prevent accurate traffic analysis in many Internet interception configurations. In particular, these countermeasures were successful against every available eavesdropping system we tested. Central to our approach is a new class of techniques that we call confusion, which, unlike cryptography or steganography, does not require cooperation by the communicating parties and, in some case, can be employed entirely by a third party not involved in the communication at all