Attackers can obtain rewards through the NFT of the flash loan winning ID

Lines of code Vulnerability details Impact The contract judges whether the user has won a prize, but only judges whether the owner of the nft with the specified ID is equal to the user's address user == IERC721EnumerableUpgradeablesettings.drawingToken.ownerOf request.currentChosenTokenId ; But i...

safeTransfer should be used instead of transferFrom in winnerClaimNFT

Lines of code Vulnerability details Impact The winner of the raffle may be a smart contract which doesn't handle NFTs, thus leaving the NFT irretrievably lost instead of being awarded to an address which can handle NFTs. Additionally, the NFT should be in the VRFNFTRandomDraw contract at the time...

In case the winner is the address(0)

Lines of code Vulnerability details Impact Temporary freezing NFT this can be more than one period Proof of Concept On VRFNFTRandomDraw.fulfillRandomWords 254 request.currentChosenTokenId = 255 randomWords0 % tokenRange + 256 settings.drawingTokenStartId; In case ownerOfrequest.currentChosenToken...

The recoverTimelock does not sufficiently protect against an admin withdrawing the NFT before a user is able to claim it

Lines of code Vulnerability details Impact When a VRFNFTRandomDraw contract is initialized, the recoverTimelock variable is set. The variable should be used to prevent the admin from calling the lastResortTimelockOwnerClaimNFT function before a certain amount of time has passed to ensure that the...

Potential race condition when claiming prize

Lines of code Vulnerability details Impact To determine whether a caller has won the raffle, the hasUserWon function of the VRFNFTRandomDraw contract queries the ownerOf function of the drawingToken contract, passing the currentChosenTokenId as argument. In essence, the function is only checking...

lastResortTimelockOwnerClaimNFT() can retrieve the token although drawing is in progress

Lines of code Vulnerability details Impact owner can retrieve the token although drawing is in progress Proof of Concept lastResortTimelockOwnerClaimNFT Be used in: " If no users ultimately claim the NFT, the admin specifies a timelock period after which they can retrieve the raffled NFT. " But i...

Owner can potentially prevent winner from claiming by starting draw after recover timelock and then calling lastResortTimelockOwnerClaimNFT

Lines of code Vulnerability details Impact The owner can call startDraw at any time, including after the recoverTimelock has expired, which means the owner can call lastResortTimelockOwnerClaimNFT and potentially reclaim the NFT immediately after the draw completes if they do not want the winner ...

Frontrunning the winnerClaimNFT is possible

Lines of code Vulnerability details Impact The winner in the NFT raffle may be frontrun if he has listed his NFT for sale on a marketplace, stealing his raffle NFT. Proof of Concept A new VRFNFTRandomDraw Clone contract is deployed using makeNewDraw, with some NFT collection as drawingToken and...

Functions of Trading contract can be reentered by Position.sol#mint

Lines of code Vulnerability details Impact Both the contracts of Position and Trading may not work correctly. Proof of Concept The Position.solmint calls safeMint will trigger a checkOnERC721Received callback, which can be used to reenter. Crackers can use this vulnerability to attack the protoco...

Draw admin/owner can rug the winner after recoverTimelock expires.

Lines of code Vulnerability details Impact The admin/owner of VRFNFTRandomDraw can wait for recoverTimelock to expire before making the draw. This way he can use lastResortTimelockOwnerClaimNFT to take back the reward NFT from the contract without any time to allow for the winner to claim. He cou...

A compromised owner of VRFNFTRandomDraw can claim the NFT to another accomplice addresss

Lines of code Vulnerability details Impact Detailed description of the impact of this finding. A compromised owner of VRFNFTRandomDraw can claim the NFT to another accomplice addresss Proof of Concept Provide direct links to all referenced code in GitHub. Add screenshots, logs, or any other...

Draw organizer can time draws so that user's have the illusion of fair random, but draw can be cancelled.

Lines of code Vulnerability details Description In RandomDraw, host can call startDraw or redraw to request a Chainlink random number, which will be used to select the winning user. They may then collect the prize NFT using winnerClaimNFT. The issue is that in the two draw functions, it is never...

Bad actor can burn VRFCoordinatorV2 LINK's balance

Lines of code Vulnerability details Impact All VRFNFTRandomDraw instances share the same VRFCoordinatorV2 address, and LINK fees are deducted from this smart contract. There are a couple of issues that may be exploited by malicious actor to overinflate calls to VRF and in lead to griefing, e.g. B...

The way the winner claiming NFT is vulnerable to flashloan attack.

Lines of code Vulnerability details Impact The way the winner claiming NFT is vulnerable to flashloan attack. Proof of Concept This kind of attack is similar to ApeCoin Airdrop attack. To determine who is winng the current drawing, there is a hashUserWon function: function hasUserWonaddress user...

In consistent parameters settings can break the business logic

Lines of code Vulnerability details Impact The usual business logic of the raffle should be that: If a user wins a raffle, he can always claim the NFT before a redraw can be initialized. However, the settings parameters can be set to inconsistent so that a winner may not be able to claim the NFT...

Malicious drawingToken can make bad actor claim the raffle NFT

Lines of code Vulnerability details Description Malicious drawingToken address passed into factory.makeNewDraw can claim the raffle NFT. It can be exploited via a social engineering attack or another scenario is that a malicious owner can pretend to make a raffle with a malicious drawingToken and...

The raffle could be slightly unfair as the owner of NFT ID which is closer to drawingTokenStartId could have more chance to win

Lines of code Vulnerability details Impact The raffle could be slightly unfair as the owner of NFT ID which is closer to drawingTokenStartId could have more chance to win. Proof of Concept As written in , "We want to raffle away a single NFT token based off of another NFT collection or drawingTok...

Use of resignOwnership can lead to stuck NFT in contract

Lines of code Vulnerability details Impact Contract OwnableUpgradeable has a resignOwnership function that, if called, can potentially cause the loss of the NFT after a draw has been started. Proof of Concept These are the steps/conditions that make this issue happen: When the owner calls...

Generalized frontrunning risk for claiming winnings due to request.currentChosenTokenId being public

Lines of code Vulnerability details Impact The function VRFNFTRandomDraw.sol:fulfillRandomWords called by Chainlink receives an array of random words, and uses it to choose a random offset by which the winning tokenId is selected. The chosen tokenId is stored on the public request variable in the...

The NFT can be transferred to the owner immediately after startDraw()

Lines of code Vulnerability details lastResortTimelockOwnerClaimNFT as the name says is used in case the winning user doesn't retrieve the won NFT token and in such case the owner can rescue the NFT from the contract. The mentioned function can be only called after a certain period is passed: if...