Many machine learning (ML) models are Python pickle files under the hood, and it makes sense. The use of pickling conserves memory, enables start-and-stop model training, and makes trained models portable (and, thereby, shareable). Pickling is easy to implement, is built into Python without requiring additional dependencies, and supports serialization of custom […]
It is a truism in modern software development that a robust continuous integration (CI) system is necessary. But many projects suffer from CI that feels brittle, frustrates developers, and actively impedes development velocity. Why is this? What can you do to avoid the common CI pitfalls? Continuous Integration Needs a Purpose CI […]
Zero-knowledge (ZK) proofs are gaining popularity, and exciting new applications for this technology are emerging, particularly in the blockchain space. So we’d like to shine a spotlight on an interesting source of implementation bugs that we’ve seen—the Fiat Shamir transformation. A ZK proof can be either interactive, where the […]
If you’re thinking of writing a paper describing an exciting novel approach to smart contract analysis and want to know what reviewers will be looking for, you’ve come to the right place. Deadlines for many big conferences (ISSTA tool papers, ASE, FSE, etc.) are approaching, as is our own Workshop on Smart Contract Analysis, so […]
Trail of Bits sponsored the recent justCTF competition, and our engineers helped craft several of the challenges, including D0cker, Go-fs, Pinata, Oracles, and 25519. In this post we’re going to cover another of our challenges, titled PDF is broken, and so is this file. It demonstrates some of the PDF file format’s idiosyncrasies in a […]
On December 3rd, Aave deployed version 2 of their codebase. While we were not hired to look at the code, we briefly reviewed it the following day. We quickly discovered a vulnerability that affected versions 1 and 2 of the live contracts and reported the issue. Within an hour of sending our analysis to Aave, […]
Zero-knowledge proofs, once a theoretical curiosity, have recently seen widespread deployment in blockchain systems such as Zcash and Monero. However, most blockchain applications of ZK proofs make proof size and performance tradeoffs that are a poor fit for other use-cases. In particular, these protocols often require an elaborate trusted setup phase and optimize for proof […]
TL;DR: We’re open-sourcing a new framework, blight, for painlessly wrapping and instrumenting C and C++ build tools. We’re already using it on our research projects, and have included a set of useful actions. You can use it today for your own measurement and instrumentation needs: Why would you ever want to wrap a build tool? […]
After writing Go for years, many of us have learned the error-checking pattern down to our bones: “Does this function return an error? Ope, better make sure it’s nil before moving on.” And that’s great! This should be our default behavior when writing Go. However, rote error checking can sometimes prevent critical thinking about what […]
TL;DR: We audited an implementation of the Diamond standard proposal for contract upgradeability and can’t recommend it in its current form—but see our recommendations and upgrade strategy guidance. We recently audited an implementation of the Diamond standard code, a new upgradeability pattern. It’s a laudable undertaking, but the Diamond proposal and implementation raise many concerns. […]
Trail of Bits has manually curated a wealth of data—years of security assessment reports—and now we’re exploring how to use this data to make the smart contract auditing process more efficient with Slither-simil. Based on accumulated knowledge embedded in previous audits, we set out to detect similar vulnerable code snippets […]
TL;DR: Can we use GPUs to get 10x performance/dollar when fuzzing embedded software in the cloud? Based on our preliminary work, we think the answer is yes! Fuzzing is a software testing technique that supplies programs with many randomized inputs in an attempt to cause unexpected behavior. It’s an important, […]
During my summer internship at Trail of Bits I worked on osquery, the massively popular open-source endpoint monitoring agent used for intrusion detection, threat hunting, operational monitoring, and many other functions. Available for Windows, macOS, Linux, and FreeBSD, osquery exposes an operating system as a high-performance relational database, […]
Iterator invalidation is a common and subtle class of C++ bugs that often leads to exploitable vulnerabilities. During my Trail of Bits internship this summer, I developed Itergator, a set of CodeQL classes and queries for analyzing and discovering iterator invalidation. Results are easily interpretable by an auditor, […]
If you work on deep learning systems, check out our new tool, PrivacyRaven—it’s a Python library that equips engineers and researchers with a comprehensive testing suite for simulating privacy attacks on deep learning systems. Because deep learning enables software to perform tasks without explicit programming, it’s become ubiquitous in […]
Graphtage is a command line utility and underlying library for semantically comparing and merging tree-like structures such as JSON, JSON5, XML, HTML, YAML, and TOML files. Its name is a portmanteau of “graph” and “graftage” (i.e., the horticultural practice of joining two trees together so they grow as one). Read on for what Graphtage does differently and better, why we developed it, how it works, and directions for using it as a 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 […]
TL;DR: Sinter is the first available open-source endpoint protection agent written entirely in Swift, with support for Apple’s new EndpointSecurity API from first principles. Sinter demonstrates how to build a successful event-authorization security agent, and incorporates solutions to many of the challenges that all endpoint protection agents will face as they migrate from kernel-mode to […]
The initial release of yVault contained logic for computing the price of yUSDC that could be manipulated by an attacker to drain most (if not all) of the pool’s assets. Fortunately, Andre, the developer, reacted incredibly quickly and disabled the faulty code, securing the approximately 400,000 USD held at the time. However, this bug still […]
Smart contract authors can now express security properties in the same language they use to write their code (Solidity) and our new tool, manticore-verifier, will automatically verify those invariants. Even better, Echidna and Manticore share the same format for specifying property tests. In other words, smart contract authors can now write one property test and […]
As a company, we believe Black lives matter. In the face of continued police brutality, racial disparities in law enforcement, and limited accountability, we demand an end to systemic racism, endorse restrictions on police use of force, and seek greater accountability for police actions. We believe police misconduct, militarization of police, and unchecked abuse of […]
Upgradeable contracts are not as safe as you think. Architectures for upgradeability can be flawed, locking contracts, losing data, or sabotaging your ability to recover from an incident. Every contract upgrade must be carefully reviewed to avoid catastrophic mistakes. The most common delegatecall proxy comes with drawbacks that we’ve catalogued before. Crytic now includes a […]
The elliptic curve digital signature algorithm (ECDSA) is a common digital signature scheme that we see in many of our code reviews. It has some desirable properties, but can also be very fragile. For example, LadderLeak was published just a couple of weeks ago, which demonstrated the feasibility of key recovery with a side channel […]
TL;DR: Can we check if a mutex is locked in Go? Yes, but not with a mutex API. Here’s a solution for use in debug builds. Although you can Lock() or Unlock() a mutex, you can’t check whether it’s locked. While it is a reasonable omission (e.g., due to possible race conditions; see also Why […]
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 […]
