How much was lost in the DFX V2 hack?

The DFX V2 hack resulted in $4.0M in losses on November 10, 2022.

What attack technique was used in the DFX V2 exploit?

The DFX V2 exploit utilized Reentrancy. 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.

DFX V2 Hack

TOTAL LOST $4.0M

Medium Nov 10, 2022 Reentrancy ethereum

Affected Chain ethereum Incident surface

Recovered - No recovery reported

All-Time Rank #472 By amount stolen

Auditors 1 Prior security audit

Incident Overview

DFX is a decentralized foreign exchange protocol optimized for trading fiat-backed foreign stablecoins

This is classified as a Reentrancy . Compare similar hacks →

Incident Report

Protocol / Project DFX V2

Date of Incident November 10, 2022

Affected Chain(s) ethereum

Attack Technique Reentrancy

Classification Protocol Logic

Primary Source View Post-Mortem

Protocol Information

Protocol Type Dexs

Smart Contract Language Solidity

Protocol Twitter/X @DFXFinance

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 reentrancy 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 DFX V2's contract logic - root cause: protocol logic

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? Yes — skilled auditors routinely flag Reentrancy vulnerabilities in code review

Audited by Audit Report 1 — still lost $4.0M. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to DFX V2, these are the critical security checks that could have prevented this incident (November 2022).

Verify all logic paths related to Reentrancy are guarded by proper access controls and input validation - see the Reentrancy attack class for patterns
Check that all state-changing functions follow the Checks-Effects-Interactions (CEI) pattern to prevent reentrancy and logic ordering bugs
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

Related Attack Classes

The technique used in this hack maps to these vulnerability classes in our security curriculum:

See all Reentrancy examples →

Reentrancy

Sources & References

01
Source 1 https://twitter.com/peckshield/status/1590831589004816384?s=20&t…

Threat Assessment

Severity Level

MEDIUM

Attack Vector Reentrancy
Root Cause Protocol Logic
Year 2022

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