Google Fortifies Chrome with AI Security: New Gemini Model and Enhanced Defense Against Prompt Injections

December 8, 2025
Google Fortifies Chrome with AI Security: New Gemini Model and Enhanced Defense Against Prompt Injections
  • Google is strengthening Chrome’s agentic capabilities with layered security protections to guard against indirect prompt injections and related data risks, while planning to add a second Gemini-based model to address emerging security concerns.

  • A new security architecture for Gemini-powered web agents in Chrome enables task execution across sites for users, with an emphasis on user safety and control.

  • An observer model reviews URLs to block navigation to harmful AI-generated links and includes a prompt-injection classifier to prevent malicious instructions.

  • The observer mechanism monitors page navigation by evaluating URLs, helping to stop harmful model-driven navigations before they occur.

  • Automated red-teaming and synthetic attacks are used to probe high-risk vectors, including user-generated content, to preempt real-world exploits.

  • Transparency is provided via a work log detailing every step, with users able to stop the agent at any time.

  • The AI model cannot access saved passwords directly, and purchases or message sending require explicit user approval.

  • The approach fits a broader dual-LLM pattern (CaMeL) where one model moderates another, reflecting related academic and industry work.

  • The Alignment Critic evaluates planned actions using only metadata to veto unsafe or misaligned actions before execution, protecting the decision process from manipulation.

  • TechCrunch staff are cited, with contact information provided for further inquiries.

  • Agentic browsing enables an AI agent to autonomously perform multi-step tasks across websites, including reading content, clicking, filling forms, and taking actions for the user.

  • User control and safety are central, requiring explicit user confirmation for high-stakes actions and restricting the agent’s data access to only necessary origins.

  • Agent Origin Sets restrict the agent to relevant, origin-scoped data with read-only and read-write classifications to prevent cross-origin data leaks and arbitrary actions.

  • Gating functions assess each new origin for relevancy before navigation, reducing opportunities for compromised agents to act unpredictably.

  • The system enforces whitelists and checks so model-generated URLs are vetted and actions are logged in real time with prompts for sensitive steps like banking or purchases.

  • Industry context includes Gartner’s warnings about AI browsers, highlighting the risks of agentic features in browsers.

  • A prompt-injection classifier runs in parallel with the planner to block actions induced by manipulative content, complementing Safe Browsing and on-device defenses.

  • Google is testing defenses against simulated attacks and notes industry efforts, with open-source models from peers to detect malicious content targeting agents.

  • New whitelisting and real-time logging are in place, with explicit user confirmation required for high-sensitivity steps like logging in, accessing financial sites, or making purchases.

  • The User Alignment Critic, a Gemini-based model, independently checks each proposed action against the user’s goals and can veto unsafe or misaligned moves using metadata alone.

  • For highly sensitive tasks, user consent is required before actions such as navigating banking or medical sites and before using the password manager for logins.

  • A work log and deterministic checks keep the user in the loop, requiring confirmation before sensitive actions like navigating to banking portals, signing in, or making purchases.

  • Chrome will prompt for user confirmation before dangerous tasks and may request permission for consequential actions.

  • A layered defense combines deterministic and probabilistic methods to deter attackers from compromising agent actions.

  • A dedicated prompt-injection classifier detects social-engineering attempts, operating alongside other protections like Safe Browsing and on-device detection.

  • Chrome’s prompt-injection safeguards run in parallel with the planner to block manipulated actions and prevent undesired outcomes.

  • A prompt-injection classifier helps prevent unwanted actions, with ongoing testing against attacker vectors by researchers.

  • Related security communications note concerns about prompt injection and phishing risks in agentic features across the industry.

  • The rollout signals a broader shift toward secure, user-centric adoption of agentic browser features, balancing automation with protections.

  • Automated red-teaming and sandboxed sites generate attack simulations to continuously test defenses, with updates delivered through Chrome’s update mechanism.

  • Testing includes synthetic attacks focusing on user-generated content, ads, credential leaks, and unwanted financial transactions.

  • Industry context includes open-source detection models and broader security developments responding to prompt injection threats.

  • Industry veteran notes indirect prompt injection as the principal new threat for agentic browsing and underscores the need for robust oversight.

  • Security coverage references related stories about Chrome and browser security enhancements and high-severity vulnerabilities.

  • Chrome’s agentic features raise security concerns about user data and finances as they begin to act autonomously.

  • Initial Gemini-powered chat interfaces sparked fears of indirect prompt injection that could steer actions like financial transactions or data exfiltration.

  • Google is expanding its Vulnerability Rewards Program to offer rewards up to twenty thousand dollars for researchers who uncover breaches in the AI security boundaries.

  • Open bounty programs encourage researchers to probe the agentic system to strengthen its security posture.

  • The rewards program now includes protections for agentic boundaries, inviting security discoveries that test these new capabilities.

  • The browser enforces data access restrictions to prevent cross-origin data leaks and ensure disallowed data never reaches the AI model.

  • Google details security measures for Chrome’s agentic features, including observer models and explicit user consent for actions.

  • The User Alignment Critic analyzes action metadata to protect privacy, maintaining a separation between AI goals and web content.

Summary based on 7 sources


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