APPLICATION SECURITY

WE ACTUALLY READ
THE CODE; MOST FIRMS DON'T.
Most of the security industry runs on scanner output with human triage. That’s fine for compliance checkboxes. It won’t find the auth bypass in your custom session handling, the auth bypass used to hijack user’s accounts, or the business logic flaw that lets customers approve their own transactions. We do the advanced security work that requires actually understanding what your software does.
Discuss your project

WHAT WE DO

Design Reviews:

Catch architectural mistakes before you write a single line of code. We analyze your specification documents, system architecture, and component designs to identify security blockers before they become embedded in your codebase. This isn’t a checkbox exercise. We’re looking at how your access control model handles edge cases, whether your upgradeability mechanism creates single points of failure, how external integrations (oracles, DeFi protocols, third-party contracts) expand your attack surface, and whether your deployment and incident response plans account for realistic failure modes.

Early Stage Review:

Get expert security guidance while your architecture can still change. An Early Stage Review meets you where you are. We look at code that’s still evolving, documentation that’s incomplete, and technical solutions that might change. Rather than hunting for every bug (which would be futile in unfinished code), we focus on the decisions that matter: Is your access control model sound? Does your upgradeability approach create unnecessary risk? Are you accounting for MEV? Oracle manipulation? Blockchain reorg scenarios? Are there architectural choices that will make security harder down the line? We also evaluate your security practices, including testing coverage, tooling, documentation quality, and monitoring plans to provide concrete recommendations for improvement.

Comprehensive Security Assessment:

A complete security review of your blockchain application from smart contracts, nodes, to bridges, and everything in between. our most thorough offering. We combine manual expert review with automated analysis to examine every component that affects your security posture.

For smart contracts, we go beyond scanning for known vulnerability patterns. We analyze your business logic for economic exploits—price manipulation, flash loan attacks, improper liquidation handling, slippage vulnerabilities. We examine access control for privilege escalation paths. We test invariants through fuzzing. We check that your upgrade mechanisms don’t introduce new attack vectors. And we do this across the full range of smart contract languages: Solidity, Vyper, Cairo, Teal, Rust-based languages for Cosmos and Solana, and more.

Invariant development:

Stop finding bugs. Start preventing them. We work with your team to define function-level invariants (this operation should always be commutative) and system-level invariants (total supply should equal sum of all balances). We translate those invariants from English into Solidity. We integrate them with fuzzers like Echidna or Medusa. And we help you build the infrastructure—CI integration, cloud fuzzing, developer training—to maintain and extend these tests long after we’re gone.

RELATED SERVICES

AI/ML Security

Security for systems that learn. We assess model architectures, training pipelines, and deployment infrastructure using the same research-driven approach that earned us second place in DARPA’s AI Cyber Challenge.

Research & Engineering

Deep-dive assessments that go beyond checklists. We analyze your code, architecture, and development practices to find vulnerabilities others miss to help you fix them for good.

Cryptography

Where math meets engineering. Our team combines academic rigor with real-world implementation expertise to secure protocols from design through deployment.

Blockchain Security

Pioneering blockchain security since 2017. We build the tools auditors rely on (Slither, Echidna, Medusa) and use them to secure protocols across Ethereum, Solana, and emerging chains.

HOW WE WORK

We don't follow a checklist. We figure out how your system works, identify what matters most, and focus our effort there. Every audit is different because every application is different.

01

Understand before attacking.

We start by learning your architecture, threat model, and business requirements. This isn’t a formality, it determines where we spend our time. There’s no point in finding CSRF vulnerabilities if your threat model is nation-state actors with physical access.

02

Prioritize by actual
risk.

Component-based and control-based analysis lets us focus on high-risk areas: authentication, authorization, data validation, cryptographic operations. We review what matters, not just what’s easy.

03

Manual review first, tools second.

Automated tools find patterns and hot spots. Humans find logic flaws, edge cases, and things that shouldn’t be possible (but are). We use CodeQL, Semgrep, AI tooling developed in-house, as well as dynamic analysis to catch low-hanging fruit and validate suspicions. We believe that none of these tools are a substitute for human ingenuity.

04

Build for the
future.

When we find a bug class worth catching automatically, we write custom detection rules and give them to you. When we find systemic issues, we show you the root cause and how to prevent recurrence, both in the short-term and long-term. Our goal is for you to see fewer bugs next year, not just a report this year.

05

Verify that fixes actually work.

Findings without remediation aren’t useful. We review fixes to confirm they actually address the issue(s), and don’t introduce new ones.

DELIVERABLES

Comprehensive report with detailed findings, severity ratings, exploitation paths, and specific remediation guidance. Not vague recommendations.

Root cause analysis that explains why vulnerabilities exist, not just what they are

Custom detection rules (Semgrep/CodeQL) for vulnerability patterns specific to your codebase

Architecture and code maturity assessment identifying systemic issues and strategic improvements

Fix verification to confirm remediations actually work

Direct engineer access throughout the engagement for questions, clarifications, and asynchronous or real-time collaboration

FEATURED CUSTOMER

HUGGING FACE

Hugging Face builds Gradio, an open-source platform that lets developers quickly build and scale web applications for machine learning. They needed someone who could evaluate security across four critical scenarios: local development environments, production deployments on Hugging Face Spaces, the built-in share link functionality, and CI/CD pipeline security. They also needed a team that understood how Gradio and Hugging Face are actually used in practice to build ML apps, not just generic web security. Trail of Bits completed a review that identified 27 security issues across the Python, JavaScript, and Go codebases. The team evaluated local deployments, server implementations, and sharing infrastructure. Beyond finding bugs, Trail of Bits worked with Hugging Face to devise mitigation strategies that encouraged the ease of use that’s core to Gradio’s appeal. All findings were validated as remediated before the public release.
READ THE FULL CASE STUDY

“Trail of Bits's engineers, who bring deep backgrounds in security and Java, discovered some obscure vulnerabilities and bugs.”

Pegasys

“Trail of Bits brought tremendous protocol design expertise, careful scrutiny, and attention to detail to our review. In depth and nuanced discussions with them helped us further bolster our confidence in our design choices, improve our documentation, and ensure that we’ve carefully considered all risks to our customers’ data.”

Mrinal Wadhwa, CTO, Ockam

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VS Code

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Claude Code

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Buttercup

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FEATURED BLOG POSTS

VIEW ALL RESOURCES

WHY TRAIL OF BITS

We encourage our clients to publish our reviews. Please feel free to give them a read for how we think before you spend a single dollar. No other firm does this in as many different areas of security as Trail of Bits.
We build public tools. Buttercup, Fickling, mrva, it-depends, checksec-anywhere, SARIF Explorer, and a chunk of the Semgrep ecosystem came from our engineers. The people reviewing your code wrote the tools the industry uses to review code.
Consistency matters. The average tenure of our engineers is over five years at Trail of Bits. The person who reviews your application has probably reviewed similar systems before, and will almost certainly be here when you come back next year.
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Mailing Address

228 Park Ave S #80688

New York, NY 10003

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