Weather Witness
First Flight #40
Beginner FriendlyFoundrySolidityNFT
100 EXP
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Submission Details
Impact: medium
Likelihood: medium
Invalid

Unchecked Keeper Registration Status in Weather NFT Contract

mimis

Description

The contract fails to validate the success of Chainlink Keeper registration, potentially leading to non-functional weather update automation.

Risk

Severity: Medium
Likelihood: Medium

Summary

When registering a Chainlink Keeper for automated weather updates, the contract doesn't verify if the registration was successful via the returned upkeepId.

Vulnerability Details

Root Cause:

upkeepId = IAutomationRegistrarInterface(s_keeperRegistrar).registerUpkeep(_keeperParams);
// No validation of upkeepId

Initial State:

  1. User requests NFT with automation enabled

  2. Pays additional LINK tokens for keeper registration

  3. Registration attempt occurs

Attack Scenario:

  1. User pays for automated updates

  2. Keeper registration fails silently

  3. upkeepId is stored without validation

  4. Weather updates never occur

  5. LINK tokens wasted

Proof of Concept

// Test file demonstrating the vulnerability
function testFailedKeeperRegistration() public {
// Setup mock registrar that returns 0 (failed registration)
MockRegistrar mockRegistrar = new MockRegistrar();
weatherNft.setKeeperRegistrar(address(mockRegistrar));
// User attempts to mint with automation
vm.startPrank(user);
linkToken.approve(address(weatherNft), 1 ether);
bytes32 reqId = weatherNft.requestMintWeatherNFT{value: 1 ether}(
"123456",
"US",
true, // enable keeper
3600,
1 ether // LINK deposit
);
vm.stopPrank();
// Fulfill request
weatherNft.fulfillMintRequest(reqId);
// Assert: Failed registration was not detected
WeatherNftInfo memory nftInfo = weatherNft.s_weatherNftInfo(1);
assertEq(nftInfo.upkeepId, 0); // Invalid upkeepId stored
}

Impact

  • Failed automation setup goes undetected

  • Users lose LINK tokens

  • Weather updates don't occur

  • Poor user experience

  • System reliability compromised

Tools Used

  • Manual Review

Recommendations

Add proper validation for keeper registration:

contract WeatherNft {
error WeatherNft__KeeperRegistrationFailed();
function validateKeeperRegistration(uint256 upkeepId) internal pure {
if (upkeepId == 0) revert WeatherNft__KeeperRegistrationFailed();
}
function fulfillMintRequest(bytes32 requestId) external {
// ...existing code...
if (_userMintRequest.registerKeeper) {
// ...existing keeper registration code...
upkeepId = IAutomationRegistrarInterface(s_keeperRegistrar)
.registerUpkeep(_keeperParams);
validateKeeperRegistration(upkeepId);
// Add refund mechanism for failed registration
if (upkeepId == 0) {
IERC20(s_link).safeTransfer(
_userMintRequest.user,
_userMintRequest.initLinkDeposit
);
emit KeeperRegistrationFailed(requestId);
return;
}
}
// ...continue with NFT creation...
}
}
Updates

Appeal created

bube Lead Judge 10 days ago
Submission Judgement Published
Invalidated
Reason: Non-acceptable severity
Assigned finding tags:

[Invalid] Keeper registration status is not checked

This is informational. It is not required the keeper registration status to be checked, because if the `registerUpkeep` fails, the whole transaction will revert: https://github.com/smartcontractkit/chainlink/blob/b5e5f8bccfdc764ccba4ce8f87ce28223426c667/contracts/src/v0.8/automation/v2_1/AutomationRegistrar2_1.sol#L213

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