Security agent Jobs in Toronto, ON

Mysten Labs' mission is to advance the internet through step-function improvements in what technology makes possible. We build foundational infrastructure and products that give people, businesses, and developers new ways to interact, transact, and create value.

Our work spans on-chain finance and the emerging agent economy. Through Sui, Move, and our broader technology stack, we’re building the systems that make these experiences possible - from secure, scalable blockchain infrastructure to new ways for businesses and AI agents to interact.

Mysten Labs is looking for a hands-on Security Engineer with strong application security fundamentals and a track record of finding and fixing real vulnerabilities. You'll own bug bounty programs and external audits, secure our code and software supply chain, and build tooling that protects Mysten's products and users across the Sui ecosystem.

Responsibilities

• Run Mysten's bug bounty programs: triage, severity, responses, internal escalations, fix validation, and the budget and payouts. Turn recurring report classes into automated checks.
• Own audit engagements: scope and schedule external audits, act as the technical counterpart during the engagement, and track findings through remediation and fix validation.
• Conduct code and design reviews of systems built by Mysten, its subsidiaries and partners (Rust, TypeScript, Move). Drive issues to conclusion, including investigation and incident response, and run variant analysis so each bug class is closed everywhere it occurs.
• Own software supply chain security: dependency and CI/CD malware defenses, Endor Labs, the code security service (GitHub controls, merge bots), and the ongoing code security self-auditing service. Detect and respond to compromised packages, maintainers and build pipelines, and secure the provenance and signing of what Mysten ships.
• Build and improve anti-scam and anti-abuse tooling for the Sui ecosystem: detect phishing sites, malicious dApps, drainer contracts and other threats that target Sui users, and work with wallet teams on mitigations.
• Build security tooling: LLM-driven triage and review agents, and static and dynamic analysis (taint, call graphs, fuzzing) wired into CI and code review. Build in known-clean checks so people trust the results.

Minimum Qualifications

• Bachelor's degree in Computer Science, Computer Engineering, a relevant technical field, or equivalent practical experience.
• 3+ years of hands-on experience in security engineering, application security or product security, with a track record of finding real vulnerabilities (bug bounty reports, audit findings, CVEs or published research).
• Strong Web2 security fundamentals: XSS, CSRF, SSRF, authorization flaws, injection, deserialization, software supply chain failures, cryptographic failures.
• Proficiency in one or more of Rust, TypeScript, Python or Move, and experience reviewing and writing security-sensitive code.
• Hands-on knowledge of software supply chain attack surface: package ecosystems (npm, crates.io, PyPI), CI/CD (GitHub Actions workflow injection, token exposure, unpinned actions), and build provenance.
• Solid understanding of applied cryptography fundamentals and the common ways cryptographic systems are misused in practice.
• Experience on either side of a bug bounty program or an audit engagement.
• Strong written and verbal communication, including the ability to influence teams you have no formal authority over.
• Interest in the web3 space is required.

Preferred Qualifications

• Smart contract or wallet security: Move, Solidity or Rust-based chains; Sui's object and capability model is a plus.
• Static or dynamic program analysis: CodeQL, Semgrep, taint analysis, fuzzing, symbolic execution.
• Experience building security tooling with LLM agents (Claude Code skills or comparable), and a clear sense of where models help and where deterministic tooling has to do the work.
• Anti-phishing, anti-fraud or trust & safety experience: domain and content monitoring, crawling, classifiers, threat intelligence.
• Knowledge of recent crypto incidents and the defect classes behind them: drainer kits, DeFi frontend compromises, package-registry compromises.
• Notable bug bounty rankings, CVEs, publications or conference talks.

Employment is contingent upon the successful completion of a background check, which may include verification of employment history, education credentials, criminal history, and other relevant information.

To support an efficient and fair hiring process, we may use technology-assisted tools, including artificial intelligence (AI), to help identify and evaluate candidates. All hiring decisions are ultimately made by human reviewers.

Our team is remote first and we are hiring across the world. Here at Mysten Labs, you'll be joining a world-class team with tremendous growth potential as we bring the next billion users to web3. We raised a $300M Series B round from top Silicon Valley led venture funds like Jump Crypto, Andreessen Horowitz (a16z), Binance Labs, Redpoint, Lightspeed, Coinbase Ventures, Electric Capital, Standard Crypto, NFX, Slow Ventures, Scribble Ventures, Samsung Next, Lux Capital, among other investment firms and strategic partners. Come join us and build the future of web3!

Compensation Range: $140K - $190K

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