How much was lost in the Foxi.finance hack?

The Foxi.finance hack resulted in $16K in losses on November 17, 2020.

What attack technique was used in the Foxi.finance exploit?

The Foxi.finance exploit utilized Rugpull. Understanding this attack vector is critical for smart contract auditors and developers building secure DeFi protocols.

How can developers prevent similar smart contract attacks?

Preventing smart contract hacks requires a combination of secure coding practices, thorough security audits, and understanding common attack vectors like reentrancy, oracle manipulation, and access control flaws. Smart Contract Hacking (SCH) provides hands-on training to help developers and auditors identify and prevent vulnerabilities before deployment.

Foxi.finance Hack

TOTAL LOST $16K

Low Nov 17, 2020 Rugpull ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #1910 By amount stolen

Auditors 1 Prior security audit

Incident Overview

The contract owner (an EOA) was endowed with unlimited minting. He called the addPhase function, which has generated 500 quintillions FOXI tokens and sent them to the contract owner wallet:

https://etherscan.io/tx/0x1218cd9a…19209d

500 billion tokens were exchanged for ETH at this transaction:

https://etherscan.io/tx/0x82f7533a…0335c2

Incident Report

Protocol / Project Foxi.finance

Date of Incident November 17, 2020

Affected Chain(s) ethereum

Attack Technique Rugpull

Classification Token

Primary Source View Post-Mortem

Protocol Information

Protocol Type Yield Aggregator

Affected Token FOXI

Official Website foxi.finance/

Protocol Twitter/X @OnXFinance

Team Anonymous

Source Code Unverified

What the Attacker Needed to Succeed

Understanding the prerequisites for this type of attack helps auditors identify protocols that are most at risk and helps developers build better defenses.

Technical Knowledge Deep understanding of rugpull and Solidity and EVM internals

Capital Required Seed capital to cover gas and initial position setup

On-Chain Access Ability to interact with ethereum smart contracts and deploy a custom exploit contract

Protocol Analysis Identification of the exploitable vulnerability in Foxi.finance's contract logic - root cause: token

Execution Speed Precise transaction ordering and timing to exploit the vulnerability within a single atomic block

Obfuscation Plan A strategy to launder and move stolen funds - typically through mixers, cross-chain bridges, or decentralized DEX swaps to resist tracing

What Auditors Should Check

Could this have been caught in audit? Hard to catch — private key / OpSec failures are outside smart contract audit scope

Audited by Audit Report 1 — still lost $16K. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to Foxi.finance, these are the critical security checks that could have prevented this incident (November 2020).

Verify all logic paths related to Rugpull are guarded by proper access controls and input validation
Review privileged functions (owner, admin, governance) for potential abuse vectors - centralization risks should be documented and bounded with timelocks or multi-sigs

Master these auditing techniques with hands-on labs and real exploit scenarios in the Smart Contract Hacking course.

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Security Audit History

Audit Report 1 Report

Sources & References

01
Source 1 https://twitter.com/CaptainJackAPE/status/1327972246736891905
02
Web Archive https://web.archive.org/web/20201115124112/http://foxi.finance/

Threat Assessment

Severity Level

LOW

Attack Vector Rugpull
Root Cause Token
Year 2020

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