Federated learning (FL) relies on a central authority to oversee and aggregate model updates contributed by multiple participating parties in the training process. This centralization of sensitive model updates naturally raises concerns about the trustworthiness of the central aggregation server, as well as the potential risks associated with server failures or breaches, which could result in loss and leaks of model updates. Moreover, recent attacks have demonstrated that, by obtaining the leaked model updates, malicious actors can even reconstruct substantial amounts of private data belonging to training participants. This underscores the critical necessity to rethink the existing FL system architecture to mitigate emerging attacks in the evolving threat landscape. One straightforward approach is to fortify the central aggregator with confidential computing (CC), which offers hardware-assisted protection for runtime computation and can be remotely verified for execution integrity. However, a growing number of security vulnerabilities have surfaced in tandem with the adoption of CC, indicating that depending solely on this singular defense may not provide the requisite resilience to thwart data leaks.

Anomaly-based intrusion detection aims to learn the normal behaviors of a system and detect activity that deviates from it. One of the best ways to represent the behavior of a computer network is through provenance graphs: dynamic networks of entity interactions over time. When provenance graphs deviate from their normal behaviors, it could be indicative of a malicious actor attempting to compromise the network. However, efficiently characterizing the normal behavior of large temporal graphs is challenging. To do this, we propose EdgeTorrent, an end-to-end anomaly-based intrusion detection system for provenance graph analysis. EdgeTorrent leverages a novel high-performance message passing neural network for graph embedding over a stream of edges to capture both temporal and topological changes in the system. These embeddings are then processed by a novel adversarially trained sequence analyzer that alerts when a series of graph embeddings changes in an unexpected way. EdgeTorrent preserves temporal ordering during message passing, and its streaming-focused design allows users to conduct out-of-core inference on billion-edge graphs, faster than real-time. We show that our method outperforms state-of-the-art graph-kernel approaches on several host monitoring data sets; notably, it is the first intrusion detection system to perfectly classify the StreamSpot data set. Additionally, we show it is the best-performing method on a real-world, billion-edge data set encompassing 11 days of benign and attack data.

Training deep neural network classifiers that are certifiably robust against adversarial attacks is critical to ensuring the security and reliability of AI-controlled systems. Although numerous state-of-the-art certified training methods have been developed, they are computationally expensive and scale poorly with respect to both dataset and network complexity. Widespread usage of certified training is further hindered by the fact that periodic retraining is necessary to incorporate new data and network improvements. In this paper, we propose Certified Robustness Transfer (CRT), a general-purpose framework for reducing the computational overhead of any certifiably robust training method through knowledge transfer. Given a robust teacher, our framework uses a novel training loss to transfer the teacher’s robustness to the student. We provide theoretical and empirical validation of CRT. Our experiments on CIFAR-10 show that CRT speeds up certified robustness training by 8× on average across three different architecture generations while achieving comparable robustness to state-of-the-art methods. We also show that CRT can scale to large-scale datasets like ImageNet.

Recent studies show that the state-of-the-art deep neural networks (DNNs) are vulnerable to adversarial examples, resulting from small-magnitude perturbations added to the input. Given that that emerging physical systems are using DNNs in safety-critical situations, adversarial examples could mislead these systems and cause dangerous situations. Therefore, understanding adversarial examples in the physical world is an important step towards developing resilient learning algorithms. We propose a general attack algorithm, Robust Physical Perturbations (RP2), to generate robust visual adversarial perturbations under different physical conditions. Using the real-world case of road sign classification, we show that adversarial examples generated using RP2 achieve high targeted misclassification rates against standard-architecture road sign classifiers in the physical world under various environmental conditions, including viewpoints. Due to the current lack of a standardized testing method, we propose a two-stage evaluation methodology for robust physical adversarial examples consisting of lab and field tests. Using this methodology, we evaluate the efficacy of physical adversarial manipulations on real objects. With a perturbation in the form of only black and white stickers, we attack a real stop sign, causing targeted misclassification in 100% of the images obtained in lab settings, and in 84.8% of the captured video frames obtained on a moving vehicle (field test) for the target classifier.

Many of the everyday decisions a user makes rely on the suggestions of online recommendation systems. These systems amass implicit (e.g.,location, purchase history, browsing history) and explicit (e.g.,reviews, ratings) feedback from multiple users, produce a general consensus, and provide suggestions based on that consensus. However, due to privacy concerns, users are uncomfortable with implicit data collection, thus requiring recommendation systems to be overly dependent on explicit feedback. Unfortunately, users do not frequently provide explicit feedback. This hampers the ability of recommendation systems to provide high-quality suggestions. We introduce Heimdall, the first privacy-respecting implicit preference collection framework that enables recommendation systems to extract user preferences from their activities in a privacy respecting manner. The key insight is to enable recommendation systems to run a collector on a user's device and precisely control the information a collector transmits to the recommendation system back-end. Heimdall introduces immutable blobs as a mechanism to guarantee this property. We implemented Heimdall on the Android platform and wrote three example collectors to enhance recommendation systems with implicit feedback. Our performance results suggest that the overhead of immutable blobs is minimal, and a user study of 166 participants indicates that privacy concerns are significantly less when collectors record only specific information--a property that Heimdall enables.