The deployment script hardcodes a mistyped zkSync USDC address and bricks every claim
Executive summary
Deploy.s.sol constructs MerkleAirdrop with a mistyped token address. The configured value contains 135be where the zkSync USDC address contains 135aE. The wrong address is not the intended ERC20 contract, so the deployed airdrop cannot transfer USDC to winners.
Root cause and evidence
Deploy.s.sol:8 sets s_zkSyncUSDC to 0x1D17CbCf0D6d143135be902365d2e5E2a16538d4. The intended address is 0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4. This is not a checksum-only difference: the byte at that position is b instead of a.
Impact
The constructor permanently stores the wrong immutable token. claim later calls safeTransfer on that address and reverts, so all eligible recipients are denied their airdrop. Any funds sent to a separate/correct token contract cannot be recovered through this MerkleAirdrop.
Proof of concept
Compare the two 20-byte values or query code at the configured address on zkSync. Deploy using run(), fund the intended USDC allocation, and call claim with a valid proof. The airdrop invokes the wrong address and the transfer cannot deliver USDC.
Recommended mitigation
Replace the hardcoded value with the verified canonical zkSync USDC address, pass the address as a deployment parameter, assert address.code.length > 0, and run a fork test that transfers and claims the real token before broadcasting.
Lead Judging Commences
[H-01] Address of USDC token in `Deploy.s.sol` is wrong causing the claiming process to fail
## Description The `s_zkSyncUSDC` address in `Deploy.s.sol` is incorrectly set, leading to a failure in the claiming process. This error results in funds being stuck in the `MerkleAirdrop` contract due to the immutability of the token address. ## Impact All funds become permanently trapped in the `MerkleAirdrop` contract, rendering them inaccessible for claiming or transfer. **Proof of Concept:** To demonstrate the issue, a test contract can be added and executed using the following command: `forge test --zksync --rpc-url $RPC_ZKSYNC --mt testDeployOnZkSync` Use the RPC URL `https://mainnet.era.zksync.io` for testing. <details> <summary>Proof Of Code</summary> ```javascript // SPDX-License-Identifier: MIT pragma solidity 0.8.24; import { MerkleAirdrop, IERC20 } from "../src/MerkleAirdrop.sol"; import { Test, console2 } from "forge-std/Test.sol"; contract MerkleAirdropTest is Test { MerkleAirdrop public s_airdrop; uint256 s_amountToCollect = (25 * 1e6); // 25.000000 address s_collectorOne = 0x20F41376c713072937eb02Be70ee1eD0D639966C; bytes32 s_proofOne = 0x32cee63464b09930b5c3f59f955c86694a4c640a03aa57e6f743d8a3ca5c8838; bytes32 s_proofTwo = 0x8ff683185668cbe035a18fccec4080d7a0331bb1bbc532324f40501de5e8ea5c; bytes32[] s_proof = [s_proofOne, s_proofTwo]; address public deployer; // From Deploy.t.sol bytes32 public s_merkleRoot = 0x3b2e22da63ae414086bec9c9da6b685f790c6fab200c7918f2879f08793d77bd; address public s_zkSyncUSDC = 0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4; uint256 public s_amountToAirdrop = 4 * (25 * 1e6); function setUp() public { deployer = makeAddr("deployer"); deal(0x1D17CbCf0D6d143135be902365d2e5E2a16538d4, deployer, 100 * 1e6); vm.deal(s_collectorOne, 100 ether); } function testDeployOnZkSync() public { if (block.chainid != 324) { return; } vm.startPrank(deployer); // From here there is the code from run() s_airdrop = deployMerkleDropper(s_merkleRoot, IERC20(s_zkSyncUSDC)); // Send USDC -> Merkle Air Dropper IERC20(0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4).transfer(address(s_airdrop), s_amountToAirdrop); // end code from run vm.stopPrank(); vm.startPrank(s_collectorOne); s_airdrop.claim{ value: s_airdrop.getFee() }(s_collectorOne, s_amountToCollect, s_proof); vm.stopPrank(); } function deployMerkleDropper(bytes32 merkleRoot, IERC20 zkSyncUSDC) public returns (MerkleAirdrop) { return (new MerkleAirdrop(merkleRoot, zkSyncUSDC)); } } ``` </details> ## Recommendations To resolve the issue, update the s_zkSyncUSDC address in Deploy.s.sol to the correct value: ```diff - address public s_zkSyncUSDC = 0x1D17CbCf0D6d143135be902365d2e5E2a16538d4; + address public s_zkSyncUSDC = 0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4; ```
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