Security Researcher, Offensive AI

Hi, we're The Browser Company and we're building a better way to use the internet.

Browsers are unique in that they are one of the only pieces of software that you share with your parents as well as your kids. Which makes sense, they're our doorway to the most important things — through them we socialize with loved ones, work on our passion projects, and explore our curiosities. But on their own, they don’t actually do a whole lot, they’re kind of just there.

They don’t help us organize our messy lives or make it easier to compose our ideas. We believe that the browser could do so much more — it can empower and support the amazing things we do on the internet. That’s why we’re building one: a browser that can help us grow, create, and stay curious.

To accomplish this lofty task, we’re building a diverse team of people from different backgrounds and experiences. This isn’t optional, it’s crucial to our mission, as we need a wide range of perspectives to challenge our assumptions and shape our browser through a bold, creative lens. With that in mind, we especially encourage women, people of color, and others from historically marginalized groups to apply.

Dia is a browser enhanced with agentic capabilities. The agent reasons over untrusted content from the open web and takes real actions on the user's behalf, inside a client that sits next to everything the user is signed into. That combination produces a threat model that mostly doesn't have prior art — the interesting bugs aren't on a checklist, and the tooling to find them largely doesn't exist yet.

As a Staff Security Researcher on our security team, you'll do original offensive research against Dia including the client, agent runtime, tools and integrations it calls, and services behind them. You'll work ahead of the product, threat modeling new surfaces with the teams designing them, and reviewing features before they reach users.

You'll also eliminate bug classes by building model-driven scanning, fuzzing, and agentic hunting systems that run continuously against our code, our infrastructure, and our agent.

You’ll partner closely with the engineers who own remediation, rather than owning the fixes yourself. You'll report to the Head of Security and work across client, infrastructure, and product engineering.

• Run original offensive research against Dia, its agent, and backend services, focusing on prompt injection and indirect exfiltration, tool-call abuse, permission and provenance bypass, sandbox escape, cross-profile data access, quota and abuse-scoring bypass.

• Threat model new surface areas with the teams building them, and review features before they ship, identifying what is exploitable, what it costs an attacker, and what would have to be true to launch.

• Design and build automated vulnerability discovery including model-driven code and infrastructure scanning, fuzzing harnesses, and agentic hunting pipelines that keep working after the engagement ends.

• Eliminate entire classes of bugs in collaboration with the engineers who own the fix, then make the same issue structurally hard to reintroduce through an enforced invariant, a fail-closed default, a test, a lint, or a platform change.

• Set the standard for what 'security tested' means before a feature ships, and raise the ceiling on what the whole team can find.

• Continuous AI-assisted vulnerability discovery (first project). You’ll survey commercial scanning services, frontier models, open-source security models, and stand up a working mix against our codebase, our infrastructure, and the agent runtime.

• Agent red teaming. Plan and run regular AI-assisted red team exercises against Dia and our infrastructure, and…