Improper Balance Check

Risks:

Negative Balances: Failure to validate operations can lead to accounts having negative balances.

Overflow/Underflow: Lack of proper checks can cause integer overflow or underflow.

Recommendation:

Use utility functions for addition and subtraction that include checks for edge cases.

function transfer(from, to, amount)
    assert(Balances[from] >= amount, "Insufficient balance")
    Balances[from] = utils.subtract(Balances[from], amount)
    Balances[to] = utils.add(Balances[to], amount)
end