ERC4626 Vault Patterns

Check whether the vault implements virtual shares/assets offsets, burns dead shares on first deposit, or enforces a minimum deposit. Without these mitigations, an attacker can deposit 1 wei, donate tokens directly, and steal value from subsequent depositors through rounding.

Rounding must always favor the vault: deposit rounds shares down, mint rounds assets up, withdraw rounds shares up, and redeem rounds assets down. Rounding in the opposite direction lets attackers extract value through repeated dust operations.

Reading asset.balanceOf directly makes totalAssets manipulable through direct token donations, which distorts share pricing and reward distribution. Vaults should track assets internally with a state variable updated only through deposit and withdrawal flows.

Three common mitigations exist: adding virtual shares and assets offsets to conversion math, burning a fixed amount of dead shares to a dead address on first deposit, or enforcing a minimum deposit amount that makes the attack unprofitable.

Zero totalSupply and zero totalAssets cause division errors or incorrect 1:1 conversions, and very small deposits can mint zero shares due to rounding down. Vaults should handle these cases explicitly and reject deposits that yield zero shares.