A malicious early user can deposit() with 1 wei of asset token as the first depositor of the vault contract, and get 1 wei of shares.

[code423n4]

Lines of code

https://github.com/code-423n4/2023-01-popcorn/blob/d95fc31449c260901811196d617366d6352258cd/src/vault/Vault.sol#L294

Vulnerability details

Impact

A malicious early user can deposit() with 1 wei of asset token as the first depositor of the LToken, and get 1 wei of shares.
Then the attacker can send 10000e18 - 1 of asset tokens and inflate the price per share from 1.0000 to an extreme value of 1.0000e22 ( from (1 + 10000e18 - 1) / 1).
As a result, the future user who deposits 19999e18 will only receive 1 wei (from 19999e18 * 1 / 10000e18) of shares token.
They will immediately lose 9999e18 or half of their deposits if they redeem() right after the deposit().

Proof of Concept

https://github.com/code-423n4/2023-01-popcorn/blob/d95fc31449c260901811196d617366d6352258cd/src/vault/Vault.sol#L294

https://github.com/sherlock-audit/2022-08-sentiment-judging/blob/main/004-H/004-h.md
transmissions11/solmate#178

Tools Used

manually

Recommended Mitigation Steps

Consider requiring a minimal amount of share tokens to be minted for the first minter, and send a port of the initial mints as a reserve to the DAO.

[c4-judge]

dmvt marked the issue as duplicate of #15

[c4-sponsor]

RedVeil marked the issue as sponsor confirmed

[c4-judge]

dmvt marked the issue as not a duplicate

[c4-judge]

dmvt marked the issue as unsatisfactory:
Invalid