Practical Fine-grained Privilege Separation in Multithreaded Applications

An inherent security limitation with the classic multithreaded programming model is that all the threads share the same address space and, therefore, are implicitly assumed to be mutually trusted. This assumption, however, does not take into consideration of many modern multithreaded applications that involve multiple principals which do not fully trust each other. It remains challenging to retrofit the classic multithreaded programming model so that the security and privilege separation in multi-principal applications can be resolved. This paper proposes ARBITER, a run-time system and a set of security primitives, aimed at fine-grained and data-centric privilege separation in multithreaded applications. While enforcing effective isolation among principals, ARBITER still allows flexible sharing and communication between threads so that the multithreaded programming paradigm can be preserved. To realize controlled sharing in a fine-grained manner, we created a novel abstraction named ARBITER Secure Memory Segment (ASMS) and corresponding OS support. Programmers express security policies by labeling data and principals via ARBITER's API following a unified model. We ported a widely-used, in-memory database application (memcached) to ARBITER system, changing only around 100 LOC. Experiments indicate that only an average runtime overhead of 5.6% is induced to this security enhanced version of application

Decentralized trust in the inter-domain routing infrastructure

Inter-domain routing security is of critical importance to the Internet since it prevents unwanted traffic redirections. The current system is based on a Public Key Infrastructure (PKI), a centralized repository of digital certificates. However, the inherent centralization of such design creates tensions between its participants and hinders its deployment. In addition, some technical drawbacks of PKIs delay widespread adoption. In this paper we present IPchain, a blockchain to store the allocations and delegations of IP addresses. IPchain leverages blockchains' properties to decentralize trust among its participants, with the final goal of providing flexible trust models that adapt better to the ever-changing geopolitical landscape. Moreover, we argue that Proof of Stake is a suitable consensus algorithm for IPchain due to the unique incentive structure of this use-case, and that blockchains offer relevant technical advantages when compared to existing systems, such as simplified management. In order to show its feasibility and suitability, we have implemented and evaluated IPchain's performance and scalability storing around 350k IP prefixes in a 2.5 GB chain.Peer ReviewedPostprint (published version

On Secure Workflow Decentralisation on the Internet

Decentralised workflow management systems are a new research area, where most work to-date has focused on the system's overall architecture. As little attention has been given to the security aspects in such systems, we follow a security driven approach, and consider, from the perspective of available security building blocks, how security can be implemented and what new opportunities are presented when empowering the decentralised environment with modern distributed security protocols. Our research is motivated by a more general question of how to combine the positive enablers that email exchange enjoys, with the general benefits of workflow systems, and more specifically with the benefits that can be introduced in a decentralised environment. This aims to equip email users with a set of tools to manage the semantics of a message exchange, contents, participants and their roles in the exchange in an environment that provides inherent assurances of security and privacy. This work is based on a survey of contemporary distributed security protocols, and considers how these protocols could be used in implementing a distributed workflow management system with decentralised control . We review a set of these protocols, focusing on the required message sequences in reviewing the protocols, and discuss how these security protocols provide the foundations for implementing core control-flow, data, and resource patterns in a distributed workflow environment