State of the Art Proof-of-Work: RandomXRandomX is a new ASIC and GPU-resistant proof-of-work (PoW) algorithm originally developed for Monero, but potentially useful in any blockchain using PoW that wants to bias towards general purpose CPUs. Trail of Bits was contracted by Arweave to review this novel algorithm in a two person-week engagement and provide guidance on alternate parameter selection. But […]
Panicking the right way in GoA common Go idiom is to (1) panic, (2) recover from the panic in a deferred function, and (3) continue on. In general, this is okay, so long there are no global state changes between the entry point to the function calling defer, and the point at which the panic occurs. Such global state changes […]
Trail of Bits @ ICSE 2019 – RecapThree weeks ago, we presented our work on Slither at WETSEB, an ICSE workshop. ICSE is a top-tier academic conference, focused on software engineering. This edition of the event went very well. The organizers do their best to attract and engage industrials to the discussions. The conference had many talks in parallel. We wish we […]
Slither: The Leading Static Analyzer for Smart ContractsWe have published an academic paper on Slither, our static analysis framework for smart contracts, in the International Workshop on Emerging Trends in Software Engineering for Blockchain (WETSEB), colocated with ICSE. Our paper shows that Slither’s bug detection outperforms other static analysis tools for finding issues in smart contracts in terms of speed, robustness, and […]
Empire Hacking: Ethereum Edition 2On December 12, over 150 attendees joined a special, half-day Empire Hacking to learn about pitfalls in smart contract security and how to avoid them. Thank you to everyone who came, to our superb speakers, and to BuzzFeed for hosting this meetup at their office. Watch the presentations again It’s hard to find such rich […]
10 Rules for the Secure Use of Cryptocurrency Hardware WalletsEarlier this year, the Web3 Foundation (W3F) commissioned Trail of Bits for a security review and assessment of the risks in storing cryptocurrency. Everyone who owns cryptocurrency — from large institutions to individual enthusiasts — shares the W3F’s concerns. In service to the broader community, the W3F encouraged us to publish our recommendations for the […]
Return of the Blockchain Security Empire HackingRemember last December’s Empire Hacking? The one where we dedicated the event to sharing the best information about blockchain and smart contract security? Let’s do that again, and let’s make it a tradition; a half-day mini conference focused exclusively on a single topic every December. On December 12, please join us at Buzzfeed’s NYC offices […]
Trail of Bits @ Devcon IV RecapWe wanted to make up for missing the first three Devcons, so we participated in this year’s event through a number of talks, a panel, and two trainings. For those of you who couldn’t join us, we’ve summarized our contributions below. We hope to see you there next year. Using Manticore and Symbolic Execution to […]
How contract migration worksSmart contracts can be compromised: they can have bugs, the owner’s wallet can be stolen, or they can be trapped due to an incorrect setting. If you develop a smart contract for your business, you must be prepared to react to events such as these. In many cases, the only available solution is to deploy […]
Slither – a Solidity static analysis frameworkSlither is the first open-source static analysis framework for Solidity. Slither is fast and precise; it can find real vulnerabilities in a few seconds without user intervention. It is highly customizable and provides a set of APIs to inspect and analyze Solidity code easily. We use it in all of our security reviews. Now you […]
Introduction to Verifiable Delay Functions (VDFs)Finding randomness on the blockchain is hard. A classic mistake developers make when trying to acquire a random value on-chain is to use quantities like future block hashes, block difficulty, or timestamps. The problem with these schemes is that they are vulnerable to manipulation by miners. For example, suppose we are trying to run an […]
Ethereum security guidance for allWe came away from ETH Berlin with two overarching impressions: first, many developers were hungry for any guidance on security, and second; too few security firms were accessible. When we began taking on blockchain security engagements in 2016, there were no tools engineered for the work. Useful documentation was hard to find and hidden among […]
Rattle – an Ethereum EVM binary analysis frameworkMost smart contracts have no verified source code, but people still trust them to protect their cryptocurrency. What’s more, several large custodial smart contracts have had security incidents. The security of contracts that exist on the blockchain should be independently ascertainable. Ethereum VM (EVM) Bytecode Ethereum contracts are compiled to EVM – the Ethereum Virtual […]
Contract upgrade anti-patternsA popular trend in smart contract design is to promote the development of upgradable contracts. At Trail of Bits, we have reviewed many upgradable contracts and believe that this trend is going in the wrong direction. Existing techniques to upgrade contracts have flaws, increase the complexity of the contract significantly, and ultimately introduce bugs. To […]
State Machine Testing with EchidnaProperty-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 toolsTwo 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 EthereumToday 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 […]
Parity Technologies engages Trail of BitsWe’re helping Parity Technologies secure their Ethereum client. We’ll begin by auditing their codebase, and look forward to publishing results and the knowledge we gained in the future. Parity Technologies combines cryptography, cellular systems, peer-to-peer technology and decentralized consensus to solve the problems that have gone unaddressed by conventional server-client architecture. Their Ethereum client is designed for […]
Videos from Ethereum-focused Empire HackingOn December 12, over 150 attendees learned how to write and hack secure smart contracts at the final Empire Hacking meetup of 2017. Thank you to everyone who came, to our superb speakers, and to Datadog for hosting this meetup at their office. Watch the presentations again We believe strongly that the community should share […]
Securing Ethereum at Empire HackingIf you’re building real applications with blockchain technology and are worried about security, consider this meetup essential. Join us on December 12th for a special edition of Empire Hacking focused entirely on the security of Ethereum. Why attend? Four blockchain security experts will be sharing how to write secure smart contracts, and hack them. Two […]
Hands on the Ethernaut CTFLast week Zeppelin released their Ethereum CTF, Ethernaut. This CTF is a good introduction to discover how to interact with a blockchain and learn the basics of the smart contract vulnerabilities. The CTF is hosted on the ropsten blockchain, and you can receive free ethers for it. The browser developer console is used to interact […]
Trail of Bits joins the Enterprise Ethereum AllianceWe’re proud to announce that Trail of Bits has joined the Enterprise Ethereum Alliance (EEA), the world’s largest open source blockchain initiative. As the first information security company to join, and currently one of the industry’s top smart contract auditors, we’re excited to contribute our unparalleled expertise to the EEA. As companies begin to re-architect […]
