Vulnerability research | Fuzzing | Reversing | WebAssembly | Ethereum
2020/03/03 @ EthCC 2020
In this talk, I briefly introduce WebAssembly concepts , Ewasm specificity and opcodes/instructions. Secondly, I show how to create Ewasm smart contract and expose different techniques/tools to perform WebAssembly module closed-source analysis. Finally, we go through some basic examples to apply reversing (reverse engineering) on those Ewasm contracts and understand the logic inside.
2019/07/16 @ webassembly-security.com
Is WebAssembly already used in the wild?
The answer is of course YES and some WebAssembly modules are potentially running right now in your browser if you are using Google web services. Recently, Google was using WebAssembly for the beta version of Google Earth but also in production for services like Google Keep.
2019/06/17 @ FIRST conference 2019
More than one year after the “official” release, it’s heavily used in the wild to perform Cryptojacking (illegitimate in-browser mining) using online services, like Coinhive, that provides simple Javascript API and uses WebAssembly module to make mining even more efficient and profitable than using pure JavaScript.
First, I will introduce WebAssembly concepts and how it is currently used. Secondly, I will analyze some Cryptominer module using static and dynamic analysis (reversing, decompilation, DBI, …) applied on WebAssembly. Finally, I will expose some techniques to detect and mitigate them.
2019/05/21 @ Northsec 2019
In this workshop, I will first introduce WebAssembly concepts and why it’s consider as a “game changer for the web”. Secondly, I will expose different techniques (Static/Dynamic analysis) and tools (Octopus, Wasabi, …) to perform a WebAssembly module analysis. Finally, we will hands-on with basic examples (crackmes) and go throws some real-life cryptominer and web-browsers plugins using WebAssembly module.
Along the talk, I will only used open source tools.
link / slides (not yet) / repository
2019/04/03 @ QuoScient Medium
In part three of our mini-series (see part #1 & part #2) describing how cybercrime actors are using the Ethereum blockchain for fraudulent means, we analyze a phishing tactic that used a smart contract address. Interestingly, this smart contract is not unique and the exact same closed-source bytecode is used in more than 130 thousand smart contracts.
2019/02/18 @ EthCC 2019
At Devcon4, Vitalik annonced that WebAssembly (wasm) will be part of Ethereum 2.0 (Serenity). It’s already possible to compile smart contracts to wasm modules and run them in the Kovan network.
Using WebAssembly smart contract doesn’t mean using secure smart contract.
In this talk, I will explain what’s inside a WebAssembly module and illustrate how to analyze wasm Ethereum smart contracts to find vulnerabilities and unoptimization.
2018/09/15 @ ToorCon XX – 2018
Ethereum is the reference of smart contract platform due to the possibility to create decentralized applications (Dapps) by writing smart contracts. The Solidity source code of those smart contracts are not always available and can contains flaws (reentrancy, integer overflow/underflow, bad randomness, backdoor, ….).
Some smart contract handle thousand of ETH and can’t be modified once pushed into the blockchain. More than 90% of them doesn’t provide the associated Solidity source code and that’s also why be able to reverse and analyze Ethereum smart contract (only with the EVM bytecode) make even more sense.
2018/09/15 @ ToorCon XX – 2018
WebAssembly (WASM) is a new binary format currently developed and supported by all major browsers including Firefox, Chrome, WebKit /Safari and Microsoft Edge through the W3C. This new format have been designed to be “Efficient and fast“, “Debuggable“ and “Safe” that why it is often called as the “game changer for the web“. More than one year after the “official” release, it is not only used “for the web” by web browsers but also in some (huge) other projects like Blockchain Smart Contract platforms (EOS and Ethereum).
I will first introduce WebAssembly concepts and who currently used it in the wild. Secondly, I will show different WebAssembly VM available and explain the security measures implemented into it. Finally, I will show you, throw real life WASM modules, how to do static analysis, using techniques such as reversing, control flow and calls flow analysis, to understand deeper its behaviors. Along the talk, I will used multiple open source tools but mainly the one that I have developed and that is already available on Github (Octopus).