Publications

Our teams aspire to make discoveries that impact everyone, and core to our approach is sharing our research and tools to fuel progress in the field.

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Our teams aspire to make discoveries that impact everyone, and core to our approach is sharing our research and tools to fuel progress in the field.

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1 - 15 of 778 publications
    Preview abstract Modern user interfaces are complex composites, with elements originating from various sources, such as the operating system, apps, a web browser, or websites. Many security and privacy models implicitly depend on users correctly identifying an element's source, a concept we term ''surface attribution.'' Through two large-scale vignette-based surveys (N=4,400 and N=3,057), we present the first empirical measurement of this ability. We find that users struggle, correctly attributing UI source only 55% of the time on desktop and 53% on mobile. Familiarity and strong brand cues significantly improve accuracy, whereas UI positioning, a long-held security design concept especially for browsers, has minimal impact. Furthermore, simply adding a ''Security & Privacy'' brand cue to Android permission prompts failed to improve attribution. These findings demonstrate a fundamental gap in users' mental models, indicating that relying on them to distinguish trusted UI is a fragile security paradigm. View details
    Security Signals: Making Web Security Posture Measurable At Scale
    David Dworken
    Artur Janc
    Santiago (Sal) Díaz
    Workshop on Measurements, Attacks, and Defenses for the Web (MADWeb)
    Preview abstract The area of security measurability is gaining increased attention, with a wide range of organizations calling for the development of scalable approaches for assessing the security of software systems and infrastructure. In this paper, we present our experience developing Security Signals, a comprehensive system providing security measurability for web services, deployed in a complex application ecosystem of thousands of web services handling traffic from billions of users. The system collects security-relevant information from production HTTP traffic at the reverse proxy layer, utilizing novel concepts such as synthetic signals augmented with additional risk information to provide a holistic view of the security posture of individual services and the broader application ecosystem. This approach to measurability has enabled large-scale security improvements to our services, including prioritized rollouts of security enhancements and the implementation of automated regression monitoring. Furthermore, it has proven valuable for security research and prioritization of defensive work. Security Signals addresses shortcomings of prior web measurability proposals by tracking a comprehensive set of security properties relevant to web applications, and by extracting insights from collected data for use by both security experts and non-experts. We believe the lessons learned from the implementation and use of Security Signals offer valuable insights for practitioners responsible for web service security, potentially inspiring new approaches to web security measurability. View details
    Preview abstract Storage on Android has evolved significantly over the years, with each new Android version introducing changes aimed at enhancing usability, security, and privacy. While these updates typically help with restricting app access to storage through various mechanisms, they may occasionally introduce new complexities and vulnerabilities. A prime example is the introduction of scoped storage in Android 10, which fundamentally changed how apps interact with files. While intended to enhance user privacy by limiting broad access to shared storage, scoped storage has also presented developers with new challenges and potential vulnerabilities to address. However, despite its significance for user privacy and app functionality, no systematic studies have been performed to study Android’s scoped storage at depth from a security perspective. In this paper, we present the first systematic security analysis of the scoped storage mechanism. To this end, we design and implement a testing tool, named ScopeVerif, that relies on differential analysis to uncover security issues and implementation inconsistencies in Android’s storage. Specifically, ScopeVerif takes a list of security properties and checks if there are any file operations that violate any security properties defined in the official Android documentation. Additionally, we conduct a comprehensive analysis across different Android versions as well as a cross-OEM analysis to identify discrepancies in different implementations and their security implications. Our study identifies both known and unknown issues of scoped storage. Our cross-version analysis highlights undocumented changes as well as partially fixed security loopholes across versions. Additionally, we discovered several vulnerabilities in scoped storage implementations by different OEMs. These vulnerabilities stem from deviations from the documented and correct behavior, which potentially poses security risks. The affected OEMs and Google have acknowledged our findings and offered us bug bounties in response. View details
    Preview abstract Judging an action’s safety requires knowledge of the context in which the action takes place. To human agents who act in various contexts, this may seem obvious: performing an action such as email deletion may or may not be appropriate depending on the email’s content, the goal (e.g., to erase sensitive emails or to clean up trash), and the type of email address (e.g., work or personal). Unlike people, computational systems have often had only limited agency in limited contexts. Thus, manually crafted policies and user confirmation (e.g., smartphone app permissions or network access control lists), while imperfect, have sufficed to restrict harmful actions. However, with the upcoming deployment of generalist agents that support a multitude of tasks (e.g., an automated personal assistant), we argue that we must rethink security designs to adapt to the scale of contexts and capabilities of these systems. As a first step, this paper explores contextual security in the domain of agents and proposes contextual agent security (Conseca), a framework to generate just-in-time, contextual, and human-verifiable security policies. View details
    SMaCk: Efficient Instruction Cache Attacks via Self-Modifying Code Conflicts
    Seonghun Son
    Berk Gulmezoglu
    ACM International Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS) (2025)
    Preview abstract Self-modifying code (SMC) allows programs to alter their own instructions, optimizing performance and functionality on x86 processors. Despite its benefits, SMC introduces unique microarchitectural behaviors that can be exploited for malicious purposes. In this paper, we explore the security implications of SMC by examining how specific x86 instructions affecting instruction cache lines lead to measurable timing discrepancies between cache hits and misses. These discrepancies facilitate refined cache attacks, making them less noisy and more effective. We introduce novel attack techniques that leverage these timing variations to enhance existing methods such as Prime+Probe and Flush+Reload. Our advanced techniques allow adversaries to more precisely attack cryptographic keys and create covert channels akin to Spectre across various x86 platforms. Finally, we propose a dynamic detection methodology utilizing hardware performance counters to mitigate these enhanced threats. View details
    Permission Rationales in the Web Ecosystem: An Exploration of Rationale Text and Design Patterns
    Yusra Elbitar
    Soheil Khodayari
    Gianluca De Stefano
    Balazs Engedy
    Giancarlo Pellegrino
    Sven Bugiel
    CHI 2025, ACM
    Preview abstract Modern web applications rely on features like camera and geolocation for personalized experiences, requiring user permission via browser prompts. To explain these requests, applications provide rationales—contextual information on why permissions are needed. Despite their importance, little is known about how rationales appear on the web or their influence on user decisions. This paper presents the first large-scale study of how the web ecosystem handles permission rationales, covering three areas: (i) identifying webpages that use permissions, (ii) detecting and classifying permission rationales, and (iii) analyzing their attributes to understand their impact on user decisions. We examined over 770K webpages from Chrome telemetry, finding 3.6K unique rationale texts and 749 rationale UIs across 85K pages. We extracted key rationale attributes and assessed their effect on user behavior by cross-referencing them with Chrome telemetry data. Our findings reveal nine key insights, providing the first evidence of how different rationales affect user decisions. View details
    Preview abstract This paper presents SYMBIOSIS, an AI-powered framework to make Systems Thinking accessible for addressing societal challenges and unlock paths for leveraging systems thinking framework to improve AI systems. The platform establishes a centralized, open-source repository of systems thinking/system dynamics models categorized by Sustainable Development Goals (SDGs) and societal topics using topic modeling and classification techniques. Systems Thinking resources, though critical for articulating causal theories in complex problem spaces, are often locked behind specialized tools and intricate notations, creating high barriers to entry. To address this, we developed a generative co-pilot that translates complex systems representations - such as causal loops and stock-flow diagrams - into natural language (and vice-versa), allowing users to explore and build models without extensive technical training. Rooted in community-based system dynamics (CBSD) and informed by community-driven insights on societal context, we aim to bridge the problem understanding chasm. This gap, driven by epistemic uncertainty, often limits ML developers who lack the community-specific knowledge essential for problem understanding and formulation, often leading to misaligned causal theories and reduced intervention effectiveness. Recent research identifies causal and abductive reasoning as crucial frontiers for AI, and Systems Thinking provides a naturally compatible framework for both. By making Systems Thinking frameworks more accessible and user-friendly, we aim to serve as a foundational step to unlock future research into Responsible and society-centered AI that better integrates societal context leveraging systems thinking framework and models. Our work underscores the need for ongoing research into AI's capacity essential system dynamics such as feedback processes and time delays, paving the way for more socially attuned, effective AI systems. View details
    Google's Approach for Secure AI Agents
    Santiago (Sal) Díaz
    Kara Olive
    Google (2025)
    Preview abstract As part of Google's ongoing efforts to define best practices for secure AI systems, we’re sharing our aspirational framework for secure AI agents. We advocate for a hybrid, defense-in-depth strategy that combines the strengths of traditional, deterministic security controls with dynamic, reasoning-based defenses. This approach is grounded in three core principles: agents must have well-defined human controllers, their powers must be carefully limited, and their actions and planning must be observable. This paper reflects our current thinking and the direction of our efforts as we work towards ensuring that AI agents can be powerful, useful, and secure by default. View details
    Preview abstract The rapid emergence of generative AI models and AI powered systems has surfaced a variety of concerns around responsibility, safety, and inclusion. Some of these concerns address specific vulnerable communities, including people with disabilities. At the same time, these systems may introduce harms upon disabled users that do not fit neatly into existing accessibility classifications, and may not be addressed by current accessibility practices. In this paper, we investigate how stakeholders across a variety of job types are encountering and addressing potentially negative impacts of AI on users with disabilities. Through interviews with 25 practitioners, we identify emerging challenges related to AI’s impact on disabled users, systemic obstacles that contribute to problems, and effective strategies for impacting change. Based on these findings, we offer suggestions for improving existing processes for creating AI-powered systems and supporting practitioners in developing skills to address these emerging challenges. View details
    Security Assurance in the Age of Generative AI
    Tom Grzelak
    Kara Olive
    Moni Pande
    Google, Google, 1600 Amphitheatre Parkway, Mountain View, CA, 94043 (2025)
    Preview abstract Artificial Intelligence (AI) is a rapidly growing field known for experimentation and quick iteration, qualities that can pose challenges for traditional enterprise security approaches. Because AI introduces unique assets and surfaces—AI-driven applications, agents, assistants, vast training datasets, the models themselves, and supporting infrastructure—we’re continually updating our security controls, guided by Google’s Secure AI Framework (SAIF). To address the new challenges, we’ve expanded our traditional security approaches to cover the new attack surfaces by scanning for more types of vulnerabilities, analyzing more intel, preparing to respond to new kinds of incidents, and continually testing our controls in novel ways to strengthen our security posture. This white paper is one of a series describing our approaches to implementing Google’s SAIF. In this paper we explain how we’re applying security assurance—a cross functional effort aiming to achieve high confidence that our security features, practices, procedures, controls, and architecture accurately mediate and enforce our security policies—to AI development. Security assurance efforts help to both ensure the continued security of our AI products and address relevant policy requirements. Just as quality assurance (QA) in manufacturing meticulously examines finished products and the processes that create them to ensure they meet quality standards, security assurance serves a complementary role to the broader security efforts within an organization. Those broader security efforts span the design, implementation, and operation of controls to create secure software products; security assurance focuses on verifying and improving those efforts. Security assurance identifies gaps, weaknesses, and areas where controls may not be operating as intended, to drive continuous improvement across all security domains. It’s two-party review in action—security assurance helps build confidence that the software was not just built securely, but continues to run securely. Since AI systems—those that use AI models for reasoning—present a combination of well understood and novel risks, AI technologies require a combination of both common and novel controls. No matter how strong these controls are, a security assurance program is essential to ensure they are working as intended and that they are continually updated and improved. The paper opens with an overview of security assurance functions, covering several teams and capabilities that work together to ensure security controls are working across any software development lifecycle, including the AI development lifecycle. In particular, we focus on four functions—Red Teaming, Vulnerability Management, Detection & Response, and Threat Intelligence, and how those work together to address issues through Remediation. We then describe the features specific to AI that affect assurance functions and give examples of how we’re adapting our approaches to account for AI-specific technologies and risks. We also include guidance for organizations considering creating their own AI assurance programs, including best practices for assuring training data, models, the AI software supply chain, and product integrations. We intend this paper to be useful for a broad technical audience, including both assurance specialists who are new to AI technologies, and AI developers who are new to assurance practices. View details
    Preview abstract Responsible AI advocates for user evaluations, particularly when concerning people with disabilities, health conditions, and accessibility needs ( DHA)–wide- ranging but umbrellaed sociodemograph- ics. However, community- centered text- to- image AI’s ( T2I) evaluations are often researcher- led, situating evaluators as consumers. We instead recruited 21 people with diverse DHA to evaluate T2I by writing and editing their own T2I prompts with their preferred language and topics, in a method mirroring everyday use. We contribute user- generated terminology categories which inform future research and data collections, necessary for developing authentic scaled evaluations. We additionally surface yet- discussed DHA AI harms intersecting race and class, and participants shared harm impacts they experienced as image- creator evaluators. To this end, we demonstrate that prompt engineering– proposed as a misrepresentation mitigation– was largely ineffective at improving DHA representations. We discuss the importance of evaluator agency to increase ecological validity in community- centered evaluations, and opportunities to research iterative prompting as an evaluation technique. View details
    ExfilState: Automated Discovery of Timer-Free Cache Side Channels on ARM CPUs
    Fabian Thomas
    Michael Torres
    Michael Schwarz
    ACM Conference on Computer and Communications Security (CCS) (2025) (to appear)
    Preview
    DroidCCT: Cryptographic Compliance Test via Trillion-Scale Measurement
    Rémi Audebert
    Pedro Barbosa
    Borbala Benko
    Alex (Mac) Mihai
    László Siroki
    Catherine Vlasov
    Annual Computer Security Applications Conference (ACSAC) (2025) (to appear)
    Preview
    Preview abstract Many persistent and dangerous software vulnerabilities, including memory safety violations and code injection, arise from a common root cause: Developers inadvertently violate the implicit safety preconditions of widely-used programming constructs. These preconditions—such as pointer validity, array-access bounds, and the trustworthy provenance of code fragments to be evaluated as SQL, HTML, or JavaScript—are traditionally the developer's responsibility to ensure. In complex systems, meeting these obligations often relies on non-local, whole-program invariants that are notoriously difficult to reason about correctly, leading to vulnerabilities that are difficult to detect after the fact. This article introduces Safe Coding, a collection of software design patterns and practices designed to cost-effectively provide a high degree of assurance against entire classes of such vulnerabilities. The core principle of Safe Coding is to shift responsibility for safety from individual developers to the programming language, software libraries, and frameworks. This is achieved by systematically eliminating the direct use of risky operations—those with complex safety preconditions—in application code. Instead, these operations are encapsulated within safe abstractions: modules with public APIs that are safe by design, whose implementations fully ensure all module-internal safety preconditions through a combination of local runtime checks and by elevating safety preconditions into type invariants. Safe Coding facilitates a modular and compositional approach to whole-program safety: Difficult reasoning is localized to the implementation of safe abstractions, which undergo focused expert scrutiny. The composition of these abstractions with the majority of the codebase (which is kept free of risky operations) is then automatically verified by the language’s type checker. This form of compositional reasoning, drawing from patterns used in formal software verification, can be viewed as a semi-formal approach that balances rigor with broad applicability to large industrial codebases. We discuss the successful application of these practices at Google, where they have nearly eliminated vulnerabilities such as Cross-Site Scripting (XSS) and SQL injection, and their critical role in ensuring memory safety in Rust, collectively demonstrating a favorable cost-assurance tradeoff for achieving software safety at scale. This extended version explores the formal underpinnings of Safe Coding in detail, examining how concepts such as function contracts and modular proofs are pragmatically adapted for industrial-scale use. View details
    Preview abstract Differential privacy can be achieved in a distributed manner, where multiple parties add independent noise such that their sum protects the overall dataset with differential privacy. A common technique here is for each party to sample their noise from the decomposition of an infinitely divisible distribution. We introduce two novel mechanisms in this setting: 1) the generalized discrete Laplace (GDL) mechanism, whose distribution (which is closed under summation) follows from differences of i.i.d. negative binomial shares, and 2) The multi-scale discrete Laplace (MSDLap) mechanism, which follows the sum of multiple i.i.d. discrete Laplace shares at different scales. The mechanisms can be parameterized to have 𝑂(Δ^3𝑒^{−𝜀}) and 𝑂 (min(Δ^3𝑒^{−𝜀}, Δ^2𝑒^{−2𝜀/3})) MSE, respectively, where the latter bound matches known optimality results. Furthermore, the MSDLap mechanism has the optimal MSE including constants as 𝜀 → ∞. We also show a transformation from the discrete setting to the continuous setting, which allows us to transform both mechanisms to the continuous setting and thereby achieve the optimal 𝑂 (Δ^2𝑒^{−2𝜀/3}) MSE. To our knowledge, these are the first infinitely divisible additive noise mechanisms that achieve order-optimal MSE under pure differential privacy for either the discrete or continuous setting, so our work shows formally there is no separation in utility when query-independent noise adding mechanisms are restricted to infinitely divisible noise. For the continuous setting, our result improves upon Pagh and Stausholm’s Arete distribution which gives an MSE of 𝑂(Δ^2𝑒^{−𝜀/4}) [35]. We apply our results to improve a state of the art multi-message shuffle DP protocol from [3] in the high 𝜀 regime. View details
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