Submission Details
Severity:
Pseudo-Randomness Vulnerability.
**Description:** The `searchForEgg` function uses a pseudo-random number generator. This method is not secure as it relies on block variables (like block.timestamp and block.prevrandao) and predictable inputs (such as msg.sender and eggCounter).
**Impact:** An attacker (or miner with influence over block properties) could potentially manipulate or predict the outcome, skewing the egg-finding chance in their favor.
**Proof of Concept:** Include the following test in the `EggHuntGameTest.t.sol` file:
```solidity
function testRandomNumberGeneration() public {
uint256 eggFindThreshold = game.eggFindThreshold();
uint256 eggCounter = game.eggCounter();
uint256 random1 =
uint256(keccak256(abi.encodePacked(block.timestamp, block.prevrandao, address(this), eggCounter))) % 100;
uint256 random2 =
uint256(keccak256(abi.encodePacked(block.timestamp, block.prevrandao, address(this), eggCounter))) % 100;
assertEq(random1, random2);
}
```
**Recommended Mitigation:** For applications where fairness and unpredictability are critical, using a verifiable random function (VRF) such as Chainlink VRF is recommended.
Updates
Lead Judging Commences
m3dython 3 months ago
Submission Judgement Published Assigned finding tags:
Insecure Randomness
Insecure methods to generate pseudo-random numbers
Rewards breakdown
nSLOC
129This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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