标签：#smartcontracts

You built something. Tests pass. You're days from mainnet. Before you either skip security entirely (please don't) or spend weeks lining up a full audit, here's a self-check you can run in 20 minutes that catches the mistakes I see most often in first-time deployments. I run security reviews for small and new protocols, and the same handful of issues come up again and again. None of these need a tool — just your eyes and this list. 1. Who can call what? Open every external / public function that moves funds, mints, pauses, or upgrades. For each, ask: should a random address be able to call this? If not — is there an onlyOwner / onlyRole / require(msg.sender == ...) guarding it, in the function itself or in every internal function it calls? The classic bug isn't a missing modifier. It's a function that looks unguarded but delegates to a guarded internal one (fine), or one that looks guarded but the guard is in a branch a caller can skip (not fine). Trace the call, don't trust the signature. 2. The first-depositor trap (if you have a vault) If you mint shares from deposits (ERC-4626 or anything share-based), the first depositor can sometimes donate assets directly to the contract to inflate the share price, so the second depositor rounds down to zero shares and loses funds. Fix: virtual shares, a dead-shares mint at deploy, or a minimum-liquidity lock. OpenZeppelin's ERC-4626 handles this out of the box — a hand-rolled vault usually doesn't. 3. Reentrancy — but only the real kind Not every external call is reentrancy. It's a bug when an attacker-controlled call can re-enter and corrupt shared storage before you've updated it. Quick checks: Do you update state before the external transfer (checks-effects-interactions)? Is there a nonReentrant on functions that move value? Is the call target a trusted, immutable contract, or an arbitrary address the attacker supplies? A call to a protocol-owned contract, or a memory /local variable written after the call, is usually not

Last week I was reviewing the staking engine of a protocol before its mainnet launch. Deep in a 1,400-line contract, I found what looked like a serious bug. The reward math multiplied three values before dividing: uint256 delta = (lot.amount * rBase * midpointRate) / (RAY * RAY); Multiply-before-divide. If that intermediate product overflows uint256 , the whole epoch settlement reverts — and since every stake , withdraw , and setStake runs it, the post's funds get permanently frozen . That's a High-severity, fund-locking DoS. I had the finding half-written. lot.amount can reach 10M tokens ( 1e25 ). rBase grows with elapsed time. midpointRate can hit RAY . Multiply those and you blow past 2^256 ... I was ready to send it. Then I did the one thing that separates a real audit from false-positive spam: I checked the actual constants before writing the claim. uint256 private constant RAY = 1e18; // I'd assumed 1e27 RAY was 1e18 , not the 1e27 I'd been carrying in my head. And the interest rate had a hard cap — MAX_RATE_MAX_RAY = 5e18 , enforced even against a fully-captured timelock. I ran the numbers with the real values: For that multiplication to overflow, the protocol would need to go 2.3 × 10¹⁵ years without a single state update. Not reachable. The bug didn't exist. I deleted the finding. Why this matters more than the bug would have If I'd sent that report, here's what happens: the team's engineer clones the repo, plugs in the real constants, and realizes in ten minutes that I flagged an overflow that can't happen. Every other finding in my report now gets read with a raised eyebrow. My credibility — the entire product — is gone. This is the dirty secret of automated smart-contract auditing: the bottleneck isn't finding issues. It's not drowning the real ones in false positives. Anyone can run a scanner and paste 40 "criticals." A team that has to triage 40 flags to find the 2 that matter will — correctly — stop trusting you. The bar I hold: zero false positives o