shaka - Anyone can mint and burn tokens for/from the USSD contract

[sherlock-admin]

shaka

high

Anyone can mint and burn tokens for/from the USSD contract

Summary

Anyone can mint and burn tokens for/from the USSD contract.

Vulnerability Detail

USSD.sol functions mintRebalancer and burnRebalancer can be called by anyone.

An attacker can call mintRebalancer with an amount equal to type(uint256).max - _totalSupply. If new tokens are minted after that, the transaction will revert as _totalSupply will overflow.

Impact

Users can be prevented from mint tokens and the rebalance function will fail if ownval > 1e6 + threshold.

Code Snippet

https://github.com/sherlock-audit/2023-05-USSD/blob/main/ussd-contracts/contracts/USSD.sol#L204-L210

Tool used

Manual Review

Recommendation

Add onlyBalancer modifier to mintRebalancer and burnRebalancer functions.

Duplicate of #777