Security Engineer II, Application Security

Location: Remote, United States

About Trail of Bits

Founded in 2012 by 3 expert hackers with no investment capital, Trail of Bits is the premier place for security experts to boldly advance security and address technology's newest and most challenging risks. It has helped secure some of the world's most targeted organizations and devices. Our combination of novel research with practical solutions reduces the security risks that our clients face from emerging technologies. Our work helps drive the security industry and the public understanding of the technology underlying our world.

Cybersecurity preparedness is a moving target. Companies like ours are the tip of the spear in the fight against attackers. Our research-based and custom-engineering approach ensures that our client's capabilities are at the forefront of what's available. For companies and technologies that live and die by their security, a proactive, tailored approach is required to keep one step ahead of attackers.

Democratizing security information is essential. As part of our business, we provide ongoing informational support through blogs, whitepapers, newsletters, meetups, and open-source tools. The more the community understands security, the more they'll understand why a company like ours is so unique and valuable.

The Role

Trail of Bits seeks a Security Engineer II for our Application Security practice. You will conduct security assessments of client software, independently own substantial components or workstreams, identify and validate vulnerabilities across the application and system levels, and develop custom tooling alongside the team. You will own your analysis from discovery through client delivery and help clients understand and fix the issues you find.

This role bridges vulnerability research and applied security. Your work will be hands-on and autonomous: analyzing complex code, building custom tooling, conducting threat modeling and architecture reviews, and delivering findings that can withstand technical scrutiny.

It is distinct from roles centered on security operations, SOC work, GRC, compliance, policy, audit, or general security programs. Candidates from broader or adjacent security backgrounds should be prepared to talk through sustained, hands-on code-level security work they have personally completed.

At the Security Engineer II level, you should be able to take an ambiguous component, module, or attack surface, determine how to assess it, perform the analysis, and deliver clear findings with limited day-to-day direction. You will collaborate with a project lead and other security engineers while exercising independent technical judgment and improving the work of the team around you.

What You'll Achieve

• Security Assessment Ownership: Independently lead assessments of substantial components, modules, or systems within client engagements and own the work from scoping through delivery.
• Vulnerability Discovery and Analysis: Find and validate vulnerabilities, establish root causes and exploitation paths, assess impact, and develop proof-of-concept code when appropriate.
• Custom Security Tooling: Design and build targeted tools, harnesses, tests, or automation that expand assessment coverage and improve repeatability.
• Architecture and Threat Modeling: Review complex software architectures, identify attack surfaces, data flows, trust and privilege boundaries, and recommend practical mitigations.
• Client Communication: Produce clear, actionable findings, defend the evidence behind them, and lead technical discussions with client engineering teams.
• Team Contribution: Review other engineers' code and analysis, share techniques, and help improve the team's technical approach.
• Research and Innovation: Contribute new methods, open-source tools, and technical writing to Trail of Bits and the broader security community.

What You'll Bring

The following are requirements for this role:

• Typically 2+ years of directly relevant experience in application security, vulnerability research, security-focused software engineering, or a closely related area. Relevant experience may include professional work, research, open-source contributions, or substantial academic or independent projects; demonstrated depth and independence matter more than a strict year count.
• Repeated vulnerability-discovery experience. You can talk through vulnerabilities you personally found or validated, including how you identified them, established exploitation paths and impact, and distinguished them from false positives or low-impact defects.
• Strong code-analysis skills across unfamiliar and complex codebases, including tracing execution and data flow, identifying logic and implementation flaws, and reviewing the security implications of system design.
• Strong programming and debugging ability in at least two relevant languages, such as Rust, Go, C, C++, Python, JavaScript, TypeScript, or similar languages used in security analysis and tool development.
• Working knowledge of memory-corruption vulnerabilities and mitigations, including the ability to reason about exploit primitives, defensive mechanisms, and the practical security impact of implementation choices.
• Strong systems knowledge, including operating systems, IPC, privilege boundaries, system internals, and how applications interact with the platform around them.
• Demonstrated ability to independently scope and execute a code-level security-assessment workstream, prioritize attack surfaces, build or adapt tooling, document evidence, and deliver findings.
• Clear written and verbal communication, including experience presenting technical conclusions to software engineers or clients and contributing effectively on a distributed team.

Preferred Qualifications

These are not day-one requirements, but areas where the role can grow.

• Active or recent CTF participation, competition results, or comparable hands-on security challenges.
• Published vulnerability research, CVEs, responsible disclosures, bug bounty findings, conference presentations, or technical writeups.
• Contributions to open-source security tools, libraries, or research.
• Experience with mobile application security, mobile system internals, or binary analysis on mobile platforms.
• Experience assessing cloud platforms or infrastructure and working with tools such as Kubernetes, Helm, Terraform, or Ansible.
• Experience with kernel code, drivers, reverse engineering, fuzzing, symbolic execution, or other low-level systems work.
• Experience building security tools used by other engineers or across multiple assessments.
• Experience leading client-facing technical discussions or mentoring other security engineers.

Compensation

The base salary range for this full-time position is $140,000 to $180,000. This position is also eligible for a performance-based variable bonus. Compensation is informed by geographic location, relevant experience, and internal equity. These figures represent starting compensation for U.S.-based candidates. For specifics, please discuss with your recruiter during the hiring process.

Trail of Bits offers a comprehensive benefits package including health insurance, retirement contributions, professional development stipends, and generous PTO.

Trail of Bits, Inc. participates in E-Verify, the US federal electronic employment eligibility verification program. Learn more.

Trail of Bits is an equal-opportunity employer. We consider all qualified applicants without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, veteran status, disability, or any other characteristic protected by law, and we provide reasonable accommodations throughout the hiring process on request.

Benefits, Perks & Wellness

Trail of Bits is our people, not a place. With over 100+ employees working from every time zone across the globe, our remote-first culture is built on autonomy and trust (and backed by smile-worthy benefits) for full-time employees:

Empowered Living

• Competitive salary complemented by performance-based bonuses.
• Fully company-paid insurance packages, including health, dental, vision, disability, and life.
• A solid 401(k) plan with a 5% match of your base salary.
• 20 days of paid vacation with flexibility for more, adhering to jurisdictional regulations.

Nurturing New Beginnings

• 4 months of parental leave to cherish the arrival of new family members.
• Our team is global and remote-first. However, if you are interested in moving to NYC, we offer $10,000 in relocation assistance to support your transition.

Work & Life Enrichment

• $1,000 Working-from-Home stipend to create a comfortable and productive home office.
• Annual $750 Learning & Development stipend for continuous personal and professional growth.
• Company-sponsored all-team celebrations, including travel and accommodation, to foster community and recognize achievements.

Community Impact

• Philanthropic contribution matching up to $2,000 annually.

Trail of Bits is our people, not a place. With over 100+ employees working from every time zone across the globe, our remote-first culture is built on autonomy and trust (and backed by smile-worthy benefits) for full-time employees:

Empowered Living:

• Competitive salary complemented by performance-based bonuses.
• Fully company-paid insurance packages, including health, dental, vision, disability, and life.
• A solid 401(k) plan with a 5% match of your base salary.
• 20 days of paid vacation with flexibility for more, adhering to jurisdictional regulations.

Nurturing New Beginnings:

• 4 months of parental leave to cherish the arrival of new family members.
• Our team is global and remote-first. However, if you are interested in moving to NYC, we offer $10,000 in relocation assistance to support your transition.

Work & Life Enrichment:

• $1,000 Working-from-Home stipend to create a comfortable and productive home office.
• Annual $750 Learning & Development stipend for continuous personal and professional growth.
• Company-sponsored all-team celebrations, including travel and accommodation, to foster community and recognize achievements.

Community Impact:

• Philanthropic contribution matching up to $2,000 annually.