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.