Scaling of the glassy dynamics of soft repulsive particles: a mode-coupling approach

We combine the hyper-netted chain approximation of liquid state theory with the mode-coupling theory of the glass transition to analyze the structure and dynamics of soft spheres interacting via harmonic repulsion. We determine the locus of the fluid-glass dynamic transition in a temperature -- volume fraction phase diagram. The zero-temperature (hard sphere) glass transition influences the dynamics at finite temperatures in its vicinity. This directly implies a form of dynamic scaling for both the average relaxation time and dynamic susceptibilities quantifying dynamic heterogeneity. We discuss several qualitative disagreements between theory and existing simulations at equilibrium. Our theoretical results are, however, very similar to numerical results for the driven athermal dynamics of repulsive spheres, suggesting that `mean-field' mode-coupling approaches might be good starting points to describe these nonequilibrium dynamics.Comment: 11 pages, 8 figure

Too Big or Too Small? The PTB-PTS ICMP-based Attack against IPsec Gateways

International audienceThis work introduces the "Packet Too Big"-"Packet Too Small" ICMP based attack against IPsec gateways. We explain how an attacker having eavesdropping and packet injection capabilities, from the insecure network where he only sees encrypted packets, can force a gateway to reduce the Path MTU of an IPsec tunnel to the minimum, which triggers severe issues for the hosts behind this gateway: depending on the Path MTU discovery algorithm in use, the attack either creates a Denial of Service or major performance penalties. This attack highlights two fundamental problems that we discuss, along with potential counter-measures to mitigate the attack while keeping ICMP benefits

ICMP: an Attack Vector against IPsec Gateways

In this work we show that the Internet Control Message Protocol (ICMP) can be used as an attack vector against IPsec gateways. The main contribution of this work is to demonstrate that an attacker having eavesdropping and traffic injection capabilities in the black untrusted network (he only sees ciphered packets), can force a gateway to reduce the Path MTU of an IPsec tunnel to a minimum, which in turn creates serious issues for devices on the trusted network behind this gateway: depending on the Path MTU discovery algorithm, it either prevents any new TCP connection (Denial of Service), or it creates major performance penalties (more than 6 seconds of delay in TCP connection establishment and ridiculously small TCP segment sizes). After detailing the attack and the behavior of the various nodes, we discuss some counter measures, with the goal to find a balance between ICMP benefits and the associated risks

ICMP: an Attack Vector against IPsec Gateways

In this work we show that the Internet Control Message Protocol (ICMP) can be used as an attack vector against IPsec gateways. The main contribution of this work is to demonstrate that an attacker having eavesdropping and traffic injection capabilities in the black untrusted network (he only sees ciphered packets), can force a gateway to reduce the Path MTU of an IPsec tunnel to a minimum, which in turn creates serious issues for devices on the trusted network behind this gateway: depending on the Path MTU discovery algorithm, it either prevents any new TCP connection (Denial of Service), or it creates major performance penalties (more than 6 seconds of delay in TCP connection establishment and ridiculously small TCP segment sizes). After detailing the attack and the behavior of the various nodes, we discuss some counter measures, with the goal to find a balance between ICMP benefits and the associated risks

New Results for the PTB-PTS Attack on Tunneling Gateways

International audienceThis work analyzes the impacts of the ”Packet Too Big”- ”Packet Too Small” (PTB-PTS) Internet Control Message Protocol (ICMP) based attack against tunneling gateways. It is a follow up of a prior work [2] that detailed how to launch the PTB-PTS attack against IPsec gate- ways (for secure tunnels) and their consequences, ranging from major performance impacts (additional delays at session establishment and/or packet fragmentation) to Denial of Services (DoS).In the present work we examine a much wider range of configurations: we now consider the two IP protocol versions (previous work was lim- ited to IPv4, we add IPv6), two operating systems (previous work was limited to Linux Debian, we add a recent Ubuntu distribution as well as Windows 7), and two tunnelling protocols (previous work was limited to IPsec, we add IPIP).This work highlights the complexity of the situation as different behav- iors will be observed depending on the exact configuration. It also high- lights Microsoft’s strategy when approaching the ”minimum maximum packet size” (i.e., minimum MTU) any link technology should support: if Windows 7 mitigates the attack in IPv4 (there is no DoS), however the performance impact remains, and since the technique is inapplicable to IPv6, the attack succeeds in that case. Finally, this work highlights a fundamental problem: the impossibility to reliably identify illegitimate ICMP error packets coming from the untrusted network

A novel architecture to virtualise a hardware-bound trusted platform module

Security and trust are particularly relevant in modern softwarised infrastructures, such as cloud environments, as applications are deployed on platforms owned by third parties, are publicly accessible on the Internet and can share the hardware with other tenants. Traditionally, operating systems and applications have leveraged hardware tamper-proof chips, such as the Trusted Platform Modules (TPMs) to implement security workflows, such as remote attestation, and to protect sensitive data against software attacks. This approach does not easily translate to the cloud environment, wherein the isolation provided by the hypervisor makes it impractical to leverage the hardware root of trust in the virtual domains. Moreover, the scalability needs of the cloud often collide with the scarce hardware resources and inherent limitations of TPMs. For this reason, existing implementations of virtual TPMs (vTPMs) are based on TPM emulators. Although more flexible and scalable, this approach is less secure. In fact, each vTPM is vulnerable to software attacks both at the virtualised and hypervisor levels. In this work, we propose a novel design for vTPMs that provides a binding to an underlying physical TPM; the new design, akin to a virtualisation extension for TPMs, extends the latest TPM 2.0 specification. We minimise the number of required additions to the TPM data structures and commands so that they do not require a new, non-backwards compatible version of the specification. Moreover, we support migration of vTPMs among TPM-equipped hosts, as this is considered a key feature in a highly virtualised environment. Finally, we propose a flexible approach to vTPM object creation that protects vTPM secrets either in hardware or software, depending on the required level of assurance

Too Big or Too Small? The PTB-PTS ICMP-based Attack against IPsec Gateways

International audienceThis work introduces the "Packet Too Big"-"Packet Too Small" ICMP based attack against IPsec gateways. We explain how an attacker having eavesdropping and packet injection capabilities, from the insecure network where he only sees encrypted packets, can force a gateway to reduce the Path MTU of an IPsec tunnel to the minimum, which triggers severe issues for the hosts behind this gateway: depending on the Path MTU discovery algorithm in use, the attack either creates a Denial of Service or major performance penalties. This attack highlights two fundamental problems that we discuss, along with potential counter-measures to mitigate the attack while keeping ICMP benefits

Parallel arithmetic encryption for high-bandwidth communications on multicore/GPGPU platforms.

International audienceIn this work we study the feasibility of high-bandwidth, secure communications on generic machines equipped with the latest CPUs and General-Purpose Graphical Processing Units (GPGPU). We first analyze the suitability of current Nehalem CPU architectures. We show in particular that high performance CPUs are not sufficient by themselves to reach our performance objectives, and that encryption is the main bottleneck. Therefore we also consider the use of GPGPU, and more particularly we measure the bandwidth of the AES ciphering on CUDA. These tests lead us to the conclusion that finding an appropriate solution is extremely difficult

Can the jamming transition be described using equilibrium statistical mechanics?

When materials such as foams or emulsions are compressed, they display solid behaviour above the so-called `jamming' transition. Because compression is done out-of-equilibrium in the absence of thermal fluctuations, jamming appears as a new kind of a nonequilibrium phase transition. In this proceeding paper, we suggest that tools from equilibrium statistical mechanics can in fact be used to describe many specific features of the jamming transition. Our strategy is to introduce thermal fluctuations and use statistical mechanics to describe the complex phase behaviour of systems of soft repulsive particles, before sending temperature to zero at the end of the calculation. We show that currently available implementations of standard tools such as integral equations, mode-coupling theory, or replica calculations all break down at low temperature and large density, but we suggest that new analytical schemes can be developed to provide a fully microscopic, quantitative description of the jamming transition.Comment: 8 pages, 6 figs. Talk presented at Statphys24 (July 2010, Cairns, Australia

PALANTIR: Zero-trust architecture for Managed Security Service Provider

The H2020 PALANTIR project aims at delivering a Security-as-a-Service solution to SMEs and microenterprises via the exploitation of containerised Network Functions. However, these functions are conceived by third-party developers and can also be deployed in untrustworthy virtualisation layers, depending on the subscribed delivery model. Therefore, they cannot be trusted and require a stringent monitoring to ensure their harmlessness, as well as adequate measures to remediate any nefarious activities. This paper justifies, details and evaluates a Zero-Trust architecture supporting PALANTIR’s solution. Specifically, PALANTIR periodically attests the service and infrastructure’s components for signs of compromise by implementing the Trusted Computing paradigm. Verification addresses the firmware, OS and software using UEFI measured boot and Linux Integrity Measurement Architecture, extended to support containerised application attestation. Mitigation actions are supervised by the Recovery Service and the Security Orchestrator based on OSM to, respectively, determine the adequate remediation actions from a recovery policy and enforce them down to the lower layers of the infrastructure through local authenticated enablers. We detail an implementation prototype serving a baseline for quantitative evaluation of our work