fuzzing

Using Echidna to test a smart contract library

In this post, we’ll show you how to test your smart contracts with the Echidna fuzzer. In particular, you’ll see how to: Find a bug we discovered during the Set Protocol audit using a variation of differential fuzzing, and Specify and check useful properties for your own smart contract libraries. And we’ll demonstrate how to […]

Breaking the Solidity Compiler with a Fuzzer

Over the last few months, we’ve been fuzzing solc, the standard Solidity smart contract compiler, and we’ve racked up almost 20 (now mostly fixed) new bugs. A few of these are duplicates of existing bugs with slightly different symptoms or triggers, but the vast majority are previously unreported bugs in the compiler. This has been […]

An Echidna for all Seasons

TL;DR: We have improved Echidna with tons of new features and enhancements since it was released—and there’s more to come. Two years ago, we open-sourced Echidna, our property-based smart contract fuzzer. Echidna is one of the tools we use most in smart contract assessments. According to our records, Echidna was used in about 35% of […]

Security assessment techniques for Go projects

The Trail of Bits Assurance practice has received an influx of Go projects, following the success of our Kubernetes assessment this summer. As a result, we’ve been adapting for Go projects some of the security assessment techniques and tactics we’ve used with other compiled languages. We started by understanding the design of the language, identifying […]

Destroying x86_64 instruction decoders with differential fuzzing

TL;DR: x86_64 decoding is hard, and the number and variety of implementations available for it makes it uniquely suited to differential fuzzing. We’re open sourcing mishegos, a differential fuzzer for instruction decoders. You can use it to discover discrepancies in your own decoders and analysis tools! In the beginning, there was instruction decoding Decompilation and […]

Watch Your Language: Our First Vyper Audit

A lot of companies are working on Ethereum smart contracts, yet writing secure contracts remains a difficult task. You still have to avoid common pitfalls, compiler issues, and constantly check your code for recently discovered risks. A recurrent source of vulnerabilities comes from the early state of the programming languages available. Most developers are using […]

DeepState Now Supports Ensemble Fuzzing

(Francis Lewis High School, Queens, NY)
We are proud to announce the integration of ensemble fuzzing into DeepState, our unit-testing framework powered by fuzzing and symbolic execution. Ensemble fuzzing allows testers to execute multiple fuzzers with varying heuristics in a single campaign, while maintaining an architecture for synchronizing generated input seeds across […]

User-Friendly Fuzzing with Sienna Locomotive

Fuzzing is a great way to find bugs in software, but many developers don’t use it. We hope to change that today with the release of Sienna Locomotive, a new open-source fuzzer for Windows that emphasizes usability. Sienna Locomotive aims to make fuzzing accessible to developers with limited security expertise. Its user-oriented features make it […]

Fuzzing In The Year 2000

It is time for the second installment of our efforts to reproduce original fuzzing research on modern systems. If you haven’t yet, please read the first part. This time we tackle fuzzing on Windows by reproducing the results of “An Empirical Study of the Robustness of Windows NT Applications Using Random Testing” (aka ‘the NT […]

Fuzzing an API with DeepState (Part 1)

Alex Groce, Associate Professor, School of Informatics, Computing and Cyber Systems, Northern Arizona University Using DeepState, we took a handwritten red-black tree fuzzer and, with minimal effort, turned it into a much more fully featured test generator. The DeepState fuzzer, despite requiring no more coding effort, supports replay of regression tests, reduction of the size […]

How to write a rootkit without really trying

We open-sourced a fault injection tool, KRF, that uses kernel-space syscall interception. You can use it today to find faulty assumptions (and resultant bugs) in your programs. Check it out! This post covers intercepting system calls from within the Linux kernel, via a plain old kernel module. We’ll go through a quick refresher on syscalls […]

Fuzzing Like It’s 1989

With 2019 a day away, let’s reflect on the past to see how we can improve. Yes, let’s take a long look back 30 years and reflect on the original fuzzing paper, An Empirical Study of the Reliability of UNIX Utilities, and its 1995 follow-up, Fuzz Revisited, by Barton P. Miller. In this blog post, […]

How to Spot Good Fuzzing Research

Of the nearly 200 papers on software fuzzing that have been published in the last three years, most of them—even some from high-impact conferences—are academic clamor. Fuzzing research suffers from inconsistent and subjective benchmarks, which keeps this potent field in a state of arrested development. We’d like to help explain why this has happened and […]

State Machine Testing with Echidna

Property-based testing is a powerful technique for verifying arbitrary properties of a program via execution on a large set of inputs, typically generated stochastically. Echidna is a library and executable I’ve been working on for applying property-based testing to EVM code (particularly code written in Solidity). Echidna is a library for generating random sequences of […]

Use our suite of Ethereum security tools

Two years ago, when we began taking on blockchain security engagements, there were no tools engineered for the work. No static analyzers, fuzzers, or reverse engineering tools for Ethereum. So, we invested significant time and expertise to create what we needed, adapt what we already had, and refine the work continuously over dozens of audits. […]

Echidna, a smart fuzzer for Ethereum

Today we released Echidna, our next-generation EVM smart fuzzer at EthCC. It’s the first-ever fuzzer to target smart contracts, and has powerful features like abstract state-machine modeling and automatic minimal test case generation. We’ve been working on it for quite some time, and are thrilled to finally share it with the world. Different interfaces for […]

The Smart Fuzzer Revolution

I recently had the privilege of giving a keynote at BSidesLisbon. I had a great time at the conference, and I’d like to thank Bruno Morisson for inviting me. If you’re into port, this is the conference for you! I recommend that anyone in the area consider attending next year. I felt there was a […]

Shin GRR: Make Fuzzing Fast Again

We’ve mentioned GRR before – it’s our high-speed, full-system emulator used to fuzz program binaries. We developed GRR for DARPA’s Cyber Grand Challenge (CGC), and now we’re releasing it as an open-source project! Go check it out. Fear GRR Bugs aren’t afraid of slow fuzzers, and that’s why GRR was designed with unique and innovative […]

A fuzzer and a symbolic executor walk into a cloud

Finding bugs in programs is hard. Automating the process is even harder. We tackled the harder problem and produced two production-quality bug-finding systems: GRR, a high-throughput fuzzer, and PySymEmu (PSE), a binary symbolic executor with support for concrete inputs. From afar, fuzzing is a dumb, brute-force method that works surprisingly well, and symbolic execution is […]

ProtoFuzz: A Protobuf Fuzzer

Google’s Protocol Buffers (protobuf) is a common method of serializing data, typically found in distributed applications. Protobufs simplify the generally error-prone task of parsing binary data by letting a developer define the type of data, and letting a protobuf compiler (protoc) generate all the serialization and deserialization code automatically. Fuzzing a service expecting protobuf-encoded structures […]