SNARKeling Treasure Hunt
First Flight #59
Beginner FriendlyGameFiFoundry
100 EXP
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Submission Details
Severity: low
Valid

withdraw() Missing Access Control

gz627

Root + Impact

Description

  • As the doc note the withdraw()function should be called by owner.

  • Due to the bug, any user can call the withdraw()function.


//file: TreasureHunt.sol
/// @notice Allow the owner to withdraw unclaimed funds after the hunt is over.
function withdraw() external { // Any user can call this function
require(claimsCount >= MAX_TREASURES, "HUNT_NOT_OVER");
​
uint256 balance = address(this).balance;
require(balance > 0, "NO_FUNDS_TO_WITHDRAW");
(bool sent, ) = owner.call{value: balance}("");
require(sent, "ETH_TRANSFER_FAILED");
​
emit Withdrawn(balance, address(this).balance);
}

Risk

Likelihood:

  • Reason 1: Due to lack of access control, any user can call withdraw()function.


Impact:

  • Impact 1: The withdraw() function lacks any access control modifier or msg.sender check, allowing any external address to trigger the withdrawal of all contract funds to the owner. While funds are sent to the correct owner address, the timing and initiation should be under owner control.

Proof of Concept

Any user can successfully call the withdraw()function when other requirements are met.

Game starts...
all treasures are discovered and rewards claimed.
A non-owner user call the `withdraw()` function.
Remaining fund is successfully sent to the owner.

Recommended Mitigation

Add access control, a predefined modifier onlyowner, to the function:

//file: TreasureHunt.sol
/// @notice Allow the owner to withdraw unclaimed funds after the hunt is over.
- function withdraw() external {
+ function withdraw() external onlyowner() {
require(claimsCount >= MAX_TREASURES, "HUNT_NOT_OVER");
Updates

Lead Judging Commences

s3mvl4d Lead Judge 18 days ago
Submission Judgement Published
Validated
Assigned finding tags:

broken access control in withdraw()

The `withdraw()` function is intended as an owner-only post-hunt recovery function, but the implementation does not actually enforce any ownership check before transferring the full remaining balance to owner. The function only requires that `claimsCount >= MAX_TREASURES` and that the contract balance is nonzero, after which it sends all ETH to the stored owner address regardless of who called the function. Therefore, the access control on the function itself is incomplete because any external account can trigger the withdrawal path once the hunt is considered over.

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