[SECURITY DISCLOSURE] Critical Vulnerability found in ERC6909.sol

[rbxict]

BUG REPORT

Contract Name: ERC6909
Severity: CRITICAL
Bugs Found: 3

Bug 1: Unprotected Function - transfer

• Description: The transfer function does not check if the sender has a sufficient balance before transferring tokens.
• Impact: This allows an attacker to transfer more tokens than they own, potentially leading to unintended behavior or exploits.
• Recommendation: Add a balance check before transferring tokens. The corrected function should look like this:

function transfer(address receiver, uint256 id, uint256 amount) public virtual returns (bool) {
    require(balanceOf[msg.sender][id] >= amount, "INSUFFICIENT_BALANCE");
    balanceOf[msg.sender][id] -= amount;
    balanceOf[receiver][id] += amount;
    emit Transfer(msg.sender, msg.sender, receiver, id, amount);
    return true;
}

Bug 2: Unprotected Function - transferFrom

• Description: The transferFrom function does not check if the sender has a sufficient balance before transferring tokens.
• Impact: This allows an attacker to transfer more tokens than the sender owns, potentially leading to unintended behavior or exploits.
• Recommendation: Add a balance check before transferring tokens. The corrected function should look like this:

function transferFrom(address sender, address receiver, uint256 id, uint256 amount) public virtual returns (bool) {
    require(balanceOf[sender][id] >= amount, "INSUFFICIENT_BALANCE");
    if (msg.sender != sender && !isOperator[sender][msg.sender]) {
        uint256 allowed = allowance[sender][msg.sender][id];
        if (allowed != type(uint256).max) allowance[sender][msg.sender][id] = allowed - amount;
    }
    balanceOf[sender][id] -= amount;
    balanceOf[receiver][id] += amount;
    emit Transfer(msg.sender, sender, receiver, id, amount);
    return true;
}

Bug 3: Unprotected Function - _burn

• Description: The _burn function does not check if the sender has a sufficient balance before burning tokens.
• Impact: This allows an attacker to burn more tokens than the sender owns, potentially leading to unintended behavior or exploits.
• Recommendation: Add a balance check before burning tokens. The corrected function should look like this:

function _burn(address sender, uint256 id, uint256 amount) internal virtual {
    require(balanceOf[sender][id] >= amount, "INSUFFICIENT_BALANCE");
    balanceOf[sender][id] -= amount;
    emit Transfer(msg.sender, sender, address(0), id, amount);
}

Additional Recommendations

• Consider adding input validation for id and amount parameters to prevent potential reentrancy attacks.
• Add events for OperatorSet and Approval functions to improve contract transparency.
• Review the contract's logic and ensure that it aligns with the ERC6909 standard.

By addressing these issues, the contract can be made more secure and resilient to potential attacks.

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RECOMMENDATION: Immediate patch required. Bug Bounty Payout Address (ERC20): 0xe744f6791a685b0A0cC316ED44375B69361c837F

[linear]

PROTO-1280