AirDropper
AI First Flight #5
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Submission Details
Severity: high
Valid

Potentialy malicious address is being used for deployment (CGPT caught this one too)

notaltera

Deploy::s_zkSyncUSDC state variable stores a different address than what is being used to transfer USDC to the MerkleAirdrop contract, this may result in a malicious transaction on suspicious addresses everytime a claimer succesfully calls MerkleAirdrop::claim function

Description

Deploy::s_zkSyncUSDC state variable were supposed to store the actual zkSync USDC address

But the addrss is actually different than the one is used in for transfering the real USDC

@> address public s_zkSyncUSDC = 0x1D17CbCf0D6d143135be902365d2e5E2a16538d4;
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function run() public {
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@> IERC20(0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4).transfer(address(airdrop), s_amountToAirdrop);
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}

specifically on the highlighted part of the address

0x1D17CbCf0D6d143135be902365d2e5E2a16538d4
0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4

Risk

Likelihood:

When deployment processs beign executed and when claimers calls MerkleAirdrop::claim function

Impact:

potentially malicious transaction on malicious addresses

Proof of Concept

  1. Developer deploy the contract using Deploy.s.sol script file

  2. claimers calls MerkleAirdrop::claim function

  3. something bad happen

Recommended Mitigation

made sure that the address that is used for deploying the MerkleAirdrop contract and the address that is used when transfering the USDC token to the protocol is the same

contract Deploy is Script {
- address public s_zkSyncUSDC = 0x1D17CbCf0D6d143135be902365d2e5E2a16538d4;
+ address public s_zkSyncUSDC = 0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4;
bytes32 public s_merkleRoot = 0xf69aaa25bd4dd10deb2ccd8235266f7cc815f6e9d539e9f4d47cae16e0c36a05;
// 4 users, 25 USDC each
uint256 public s_amountToAirdrop = 4 * (25 * 1e6);
​
// Deploy the airdropper
function run() public {
vm.startBroadcast();
MerkleAirdrop airdrop = deployMerkleDropper(s_merkleRoot, IERC20(s_zkSyncUSDC));
// Send USDC -> Merkle Air Dropper
- IERC20(0x1d17CBcF0D6D143135aE902365D2E5e2A16538D4).transfer(address(airdrop), s_amountToAirdrop);
+ IERC20(s_zkSyncUSDC).transfer(address(airdrop), s_amountToAirdrop);
vm.stopBroadcast();
}
​
function deployMerkleDropper(bytes32 merkleRoot, IERC20 zkSyncUSDC) public returns (MerkleAirdrop) {
return (new MerkleAirdrop(merkleRoot, zkSyncUSDC));
}
}
Updates

Lead Judging Commences

ai-first-flight-judge Lead Judge about 15 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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