DatingDapp
First Flight #33
Beginner FriendlyFoundrySolidityNFT
100 EXP
View results
Previous Next
Submission Details
Severity: medium
Valid

Attackers can match themselves with other addresses they own and blackmail users of the protocol

0xdimo

Summary

Users in the protocol have no limit on the amount of matches they have. On each match all the available ETH from both users will be sent to the multiSig. This creates a healthy state where both users, who like each other will hold joint responsibility of their joint ETH.

This leaves room for the following malicious scenario:

  1. Alice has 2 addresses - Alice1 and Alice2

  2. From Alice1 she likes Alice2 and Bob

  3. Bob tries to like Alice1 back, but Alice frontruns him and likes Alice1 from Alice2

  4. The money of Alice1 and Alice2 will be sent to their joint MultiSig

  5. The money of Bob will be sent to a joint MultiSig with Alice1. This leaves Alice with not stake at all in the joint MultiSig with Bob and give her leverage to blackmail him.

PoC

modifier mintNfts() {
vm.deal(alice, 3 ether);
vm.prank(alice);
soulboundNFT.mintProfile("Alice", 25, "ipfs://profileImage");
​
vm.deal(bob, 3 ether);
vm.prank(bob);
soulboundNFT.mintProfile("Bob", 25, "ipfs://profileImage");
​
vm.deal(carol, 3 ether);
vm.prank(carol);
soulboundNFT.mintProfile("Carol", 25, "ipfs://profileImage");
_;
}
​
function test_poc_blackmail() public mintNfts {
//The bug with not updating userBalance should be fixed first
// Alice likes Bob and Carol, She matches with Bob first and then has leverage on Carol
vm.startPrank(alice);
likeRegistry.likeUser{value: 1 ether}(bob);
likeRegistry.likeUser{value: 1 ether}(carol);
vm.stopPrank();
​
vm.prank(bob);
likeRegistry.likeUser{value: 1 ether}(alice);
​
console.log("Ether in first MultiSig:", address(0xffD4505B3452Dc22f8473616d50503bA9E1710Ac).balance);
//contains ETH from Bob and Alice
​
vm.prank(carol);
likeRegistry.likeUser{value: 1 ether}(alice);
console.log("Ether in second MultiSig:", address(0x8d2C17FAd02B7bb64139109c6533b7C2b9CADb81).balance);
//contains only Carol's ETH, giving Bob leverage on Carol
}

Impact

High, as it exposes big risks for users and their funds.

Tools Used

Manual Review

Recommendations

This is a core logic in the contract. Hard to suggest, but probably only send the ETH of both users to their join multiSig, without affecting their other likes.

Updates

Appeal created

n0kto Lead Judge 6 months ago
Submission Judgement Published
Validated
Assigned finding tags:

finding_several_match_lead_to_multisig_with_no_funds

Likelihood: Medium, if anyone has 2 matches or more before reliking. Impact: Medium, the user won't contribute to the wallet.

Support

FAQs

Can't find an answer? Chat with us on Discord, Twitter or Linkedin.