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Submission Details
Severity: high
Valid

Address Case Mismatch in Deploy Script — Potential Wrong Transfer Target

pratamaajip01

[MEDIUM-1] Address Case Mismatch in Deploy Script — Potential Wrong Transfer Target

File: script/Deploy.s.sol (lines 6, 18)

Summary

The deploy script references two differently-cased versions of what appears to be the same USDC contract address. One is used to configure the airdrop contract, the other to transfer tokens into it. While Ethereum addresses are case-insensitive in execution, the inconsistency is a code quality/maintainability risk and may indicate a copy-paste error where different addresses were intended.

Vulnerability Details

// script/Deploy.s.sol
address public s_zkSyncUSDC = 0x1D17CbCf0D6d143135be902365d2e5E2a16538d4; // Line 6
// ...
IERC20(0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4).transfer(address(airdrop), s_amountToAirdrop); // Line 18

Comparing character-by-character:

  • 0x1D17CbCf0D6d143135be902365d2e5E2a16538d4

  • 0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4

These are different addresses when checksummed (EIP-55 checksum encoding differs). The contract being airdropped from (line 6) may differ from the token being used to fund it (line 18), meaning transfer could be called on a completely different token or even a non-existent contract, silently failing or sending tokens to the wrong place.

Impact

  • Deployment may silently fail to fund the airdrop contract.

  • Users would be unable to claim because the airdrop contract holds zero tokens.

  • On zkSync, silent ERC20 failures (non-reverting transfers) could go undetected.

Tools Used

  • Manual analysis

  • Address checksum comparison

Recommendations

Use a single constant for the USDC address and reference it in both places:

- address public s_zkSyncUSDC = 0x1D17CbCf0D6d143135be902365d2e5E2a16538d4;
+ address public s_zkSyncUSDC = 0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4; // verify checksum
​
function run() public {
vm.startBroadcast();
MerkleAirdrop airdrop = deployMerkleDropper(s_merkleRoot, IERC20(s_zkSyncUSDC));
- IERC20(0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4).transfer(address(airdrop), s_amountToAirdrop);
+ IERC20(s_zkSyncUSDC).transfer(address(airdrop), s_amountToAirdrop);
vm.stopBroadcast();
}
Updates

Lead Judging Commences

ai-first-flight-judge Lead Judge 6 days ago
Submission Judgement Published
Validated
Assigned finding tags:

[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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