ControlFreak: Signature Chaining to Counter Control Flow Attacks

Abstract: Many modern embedded systems use networks to communicate. This increases the attack surface: the adversary does not need to have physical access to the system and can launch remote attacks. By exploiting software bugs, the attacker might be able to change the behavior of a program. Security violations in safety-critical systems are particularly dangerous since they might lead to catastrophic results. Hence, safety-critical software requires additional protection. We present an approach to detect and prevent control flow attacks. Such attacks maliciously modify program's control flow to achieve the desired behavior. We develop ControlFreak, a hardware watchdog to monitor program execution and to prevent illegal control flow transitions. The watchdog employs chained signatures to detect any modification of the instruction stream and any illegal jump in the program even if signatures are maliciously modified

Scalable error isolation for distributed systems: modeling, correctness proofs, and additional experiments

This technical report complements the paper entitled “Scalable error isolation for distributed systems” published at USENIX NSDI 15

ShieldBox: Secure Middleboxes using Shielded Execution

Middleboxes that process confidential data cannot be securely deployed in untrusted cloud environments. To securely outsource middleboxes to the cloud, state-of-the-art systems advocate network processing over the encrypted traffic. Unfortunately, these systems support only restrictive functionalities, and incur prohibitively high overheads. This motivated the design of ShieldBox—a secure middlebox framework for deploying high-performance network functions (NFs) over untrusted commodity servers. ShieldBox securely processes encrypted traffic inside a secure container by leveraging shielded execution. More specifically, ShieldBox builds on hardware-assisted memory protection based on Intel SGX to provide strong confidentiality and integrity guarantees. For middlebox developers, ShieldBox exposes a generic interface based on Click to design and implement a wide-range of NFs using its out-of-the-box elements and C++ extensions. For network operators, ShieldBox provides configuration and attestation service for seamless and verifiable deployment of middleboxes. We have implemented ShieldBox supporting important end-to-end features required for secure network processing, and performance optimizations. Our extensive evaluation shows that ShieldBox achieves a near-native throughput and latency to securely process confidential data at line rate

LightBox: Full-stack Protected Stateful Middlebox at Lightning Speed

Running off-site software middleboxes at third-party service providers has been a popular practice. However, routing large volumes of raw traffic, which may carry sensitive information, to a remote site for processing raises severe security concerns. Prior solutions often abstract away important factors pertinent to real-world deployment. In particular, they overlook the significance of metadata protection and stateful processing. Unprotected traffic metadata like low-level headers, size and count, can be exploited to learn supposedly encrypted application contents. Meanwhile, tracking the states of 100,000s of flows concurrently is often indispensable in production-level middleboxes deployed at real networks. We present LightBox, the first system that can drive off-site middleboxes at near-native speed with stateful processing and the most comprehensive protection to date. Built upon commodity trusted hardware, Intel SGX, LightBox is the product of our systematic investigation of how to overcome the inherent limitations of secure enclaves using domain knowledge and customization. First, we introduce an elegant virtual network interface that allows convenient access to fully protected packets at line rate without leaving the enclave, as if from the trusted source network. Second, we provide complete flow state management for efficient stateful processing, by tailoring a set of data structures and algorithms optimized for the highly constrained enclave space. Extensive evaluations demonstrate that LightBox, with all security benefits, can achieve 10Gbps packet I/O, and that with case studies on three stateful middleboxes, it can operate at near-native speed.Comment: Accepted at ACM CCS 201

LibSEAL: revealing service integrity violations using trusted execution

Users of online services such as messaging, code hosting and collaborative document editing expect the services to uphold the integrity of their data. Despite providers’ best efforts, data corruption still occurs, but at present service integrity violations are excluded from SLAs. For providers to include such violations as part of SLAs, the competing requirements of clients and providers must be satisfied. Clients need the ability to independently identify and prove service integrity violations to claim compensation. At the same time, providers must be able to refute spurious claims. We describe LibSEAL, a SEcure Audit Library for Internet services that creates a non-repudiable audit log of service operations and checks invariants to discover violations of service integrity. LibSEAL is a drop-in replacement for TLS libraries used by services, and thus observes and logs all service requests and responses. It runs inside a trusted execution environment, such as Intel SGX, to protect the integrity of the audit log. Logs are stored using an embedded relational database, permitting service invariant violations to be discovered using simple SQL queries. We evaluate LibSEAL with three popular online services (Git, ownCloud and Dropbox) and demonstrate that it is effective in discovering integrity violations, while reducing throughput by at most 14%