Impossible Finance

Submit a Bug
18 June 2021
Live since
KYC required
Maximum bounty

Program Overview

Impossible Finance uses decentralised financial protocols to give everyone the same access to financial products, which were previously only available to institutions and select individuals. Impossible Finance has a vision to level the playing field by building a fair, more accessible open financial system for all.

Further resources regarding Impossible Finance can be found on their website,

The bug bounty program is focused around its smart contracts and is mostly concerned with the loss of user funds and other smart contract risks.

Rewards by Threat Level

Rewards are distributed according to the impact of the vulnerability based on the Immunefi Vulnerability Severity Classification System. This is a simplified 5-level scale, with separate scales for websites/apps and smart contracts/blockchains, encompassing everything from consequence of exploitation to privilege required to likelihood of a successful exploit.

Smart Contract critical payouts have a maximum total payout of 10% of the funds that are directly potentially affected with a payout floor of USD 50 000. The estimated maximum payout is based on the Total Value Locked (TVL) in the Impossible Finance but is explicitly only an estimate and only the actual active amount at the time of reporting will be considered. The actual active amount of staked funds can be found on

Payouts are handled by the Impossible Finance team directly and are denominated in USD. However, payouts are done in BUSD. For Critical payouts, up to 80% of the reward may be in the project token, IF.

Smart Contracts and Blockchain

USD $50,000 - 10% of Funds at Risk (max est. USD $94,000)
USD $20,000
USD $5,000
USD $1,000

Assets in Scope

The ImpossibleRouter01.sol smart contract is considered as out-of-scope of the bug bounty program.

Please note that the current settings in the repository are optimized for running our test cases. These settings include changing the duration of “ONE_DAY” to 50 binance smart chain blocks (as opposed to 28800) and commenting out require statements in modifiers such as onlyGovernance in ImpossiblePair.sol and setRouter in ImpossibleFactory.sol. Specifically, we are aware that with these settings, if a router is not initialized upon contract deployment, an adversary can call setRouter and link a malicious router which takes advantage of how cheapSwap in ImpossiblePair.sol doesn’t perform K invariant checks. The scope of the bug bounty covers the “production version” of these contracts in which the 3 variables are uncommented instead of commented.

Prioritized Vulnerabilities

We are especially interested in receiving and rewarding vulnerabilities of the following types:

  • Re-entrancy
  • Logic errors
    • including user authentication errors
  • Solidity/EVM details not considered
    • including integer over-/under-flow
    • including unhandled exceptions
  • Trusting trust/dependency vulnerabilities
    • including composability vulnerabilities
  • Oracle failure/manipulation
  • Novel governance attacks
  • Economic/financial attacks
    • including flash loan attacks
  • Congestion and scalability
    • including running out of gas
    • including block stuffing
    • including susceptibility to frontrunning
  • Consensus failures
  • Cryptography problems
    • Signature malleability
    • Susceptibility to replay attacks
    • Weak randomness
    • Weak encryption
  • Susceptibility to block timestamp manipulation
  • Missing access controls / unprotected internal or debugging interfaces

Out of Scope & Rules

The following vulnerabilities are excluded from the rewards for this bug bounty program:

  • Attacks that the reporter has already exploited themselves, leading to damage
  • Attacks requiring access to leaked keys/credentials
  • Attacks requiring access to privileged addresses (governance, strategist)
  • Incorrect data supplied by third party oracles
    • Not to exclude oracle manipulation/flash loan attacks
  • Basic economic governance attacks (e.g. 51% attack)
  • Lack of liquidity
  • Best practice critiques
  • Sybil attacks

The following activities are prohibited by bug bounty program:

  • Any testing with mainnet or public testnet contracts; all testing should be done on private testnets
  • Any testing with pricing oracles or third party smart contracts
  • Attempting phishing or other social engineering attacks against our employees and/or customers
  • Any testing with third party systems and applications (e.g. browser extensions) as well as websites (e.g. SSO providers, advertising networks)
  • Any denial of service attacks
  • Automated testing of services that generates significant amounts of traffic
  • Public disclosure of an unpatched vulnerability in an embargoed bounty