EVM Reverse Engineering Challenge 0x00

It’s been a while since I don’t blog, so I think it’s time. I’ve been writing an Sandwich bot, mostly in the night after work, that according to my forecast it will take me my whole life :). In case you don’t know what is a sandwich bot let me tell you is not a robot that makes sandwich, that would be awesome. Just google MEV sandwich Ethereum, that should give you a good start. Thanks to this I’ve learned more and more about EVM(Ethereum Virtual Machine) in general, learning how to optimize a contract to spend less and less gas. This post is not about MEV or explaining what it is, there’s a lot of information about it online. Instead, is more to start doing something similar to Reverse Engineering challenges by Dennis Yurichev, but focus on EVM instead of traditional reverse engineering.

This blog will be the first of a series of blog, that I’ll try to keep up, if laziness or another millionaire idea, like a sandwich bot, doesn’t distract me. The format of the challenges will be quite simple, I’ll share with you one contract addresses in the Ethereum Mainnet or TON Mainnet(not sure about this yet), the contract will have 1 USDT, your goal will be to exploit this contract and get the 1 USDT for you. Given that I’m far from being rich, I’ll limit the number of challenges to 100, I hope I’ll have enough material for it. After someone exploits the contract, the 1 USDT won’t be in the contract removing the “incentive” for someone else to exploit the contract again. I know 1 USDT is not such a big incentive neither. Is better to be the first, you’ll get a whole 1 USDT, WAOOO.

The challenges will be from easier to harder, I’ll try by all means to keep it in that way, but given that I’ll be also learning with this I cannot assure you that. In order to exploit this contracts is recommended that you firstly simulate your txns, in Ethereum that can be done quite precise with Tenderly, temper, in TON I really don’t know of a good tool for that. Nevertheless this first challenge is on Ethereum. Please simulate before submitting a txn, don’t spend gas for nothing.

Enough talk, show me the stuff I want my 1 USDT!!! I’m sure this what you are thinking at the moment, you want to crack this shit and get the 1 USDT to show off with your friends. Don’t worry my friend, here is the contrat address:

0xC3fA91C26307EA9c59334c55e23d8bf19f555Ea8

Feel free to exploit it, and earn that 1 USDT.

HINT: 2 + 2 = ?

PS: possible the txn will cost you more than 1 USDT, because well is Ethereum…