Logic vulnerabilities are often the most dangerous bugs in DeFi. Unlike reentrancy or overflow errors, they don't always trigger standard static analysis tools. They hide in plain sight, disguised as "intended functionality."
In this article, I want to share a recent security assessment I performed, where a critical logic flaw could have allowed an attacker to drain the entire vault.
The Anatomy of the Bug: The "Arbiter" Flaw
In the original implementation of the RetoSwap vault, the logic for registering an "Arbiter" (a trusted entity authorized to move funds) was flawed:
Solidity
