AirDropper
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Submission Details
Severity: high
Valid

Deploy script funds the airdrop with a different USDC address than the constructor (typo), breaking the airdrop

hopeh

Description


The deploy script constructs the airdrop with one token address but funds it from a different address — the two hardcoded USDC addresses differ by a single character (...135be902...vs ...135ae902...):


// Deploy.s.sol
address public s_zkSyncUSDC = 0x1D17CbCf0D6d143135be902365d2e5E2a16538d4; // @> address A, used to build the airdrop
...
MerkleAirdrop airdrop = deployMerkleDropper(s_merkleRoot, IERC20(s_zkSyncUSDC)); // @> airdrop.i_airdropToken = A
// Send USDC -> Merkle Air Dropper
IERC20(0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4).transfer(address(airdrop), s_amountToAirdrop); // @> funds from address B (!= A)
```
​
`0x1D17CbCf0D6d143135**be**902365d2e5E2a16538d4` (used in the constructor) is NOT the same address as `0x1d17CBcF0D6D143135**aE**902365D2E5e2A16538D4` (used to fund). The airdrop's `i_airdropToken` is set to A, but the 100 USDC is transferred from/into contract B.
​
## Risk
​
**Likelihood: High**
​
- This is deterministic: the deploy script as written always uses the mismatched addresses, so every deployment is affected.
​
**Impact: High**
​
- The airdrop contract holds balance of token B (or nothing, if B is not the real USDC) while `claim` calls `i_airdropToken.safeTransfer(...)` on token A. Claims therefore revert (the airdrop holds 0 of token A) and/or the funding transfer sends 100 USDC to an address that is not the deployed airdrop as intended. The airdrop is non-functional and the funding tokens are misdirected — loss/lock of the airdropped funds.
​
## Proof of Concept
​
```solidity
// addrA = 0x1D17CbCf0D6d143135be902365d2e5E2a16538d4 (constructor token)
// addrB = 0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4 (funding token) -> addrA != addrB
// airdrop.i_airdropToken == addrA; funds moved via addrB.
// claim() -> addrA.safeTransfer(account, amount) -> reverts (airdrop holds 0 of addrA).
```
​
## Recommended Mitigation
​
Use a single source of truth for the token address (the `s_zkSyncUSDC` constant) in both the constructor and the funding transfer:
​
```solidity
IERC20(s_zkSyncUSDC).transfer(address(airdrop), s_amountToAirdrop); // same address as the constructor
```
Updates

Lead Judging Commences

ai-first-flight-judge Lead Judge about 2 hours 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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