Fegex Hack

TOTAL LOST $900K
Low Missing Access Control base bsc ethereum

Summarize with AI

Affected Chain base 3 chains affected
Recovered - No recovery reported
All-Time Rank #836 By amount stolen
Auditors 1 Prior security audit

Incident Overview

The All-in-One exchange

Incident Report

Protocol / Project Fegex
Date of Incident
Affected Chain(s) base bsc ethereum
Attack Technique Missing Access Control
Classification Protocol Logic
Primary Source View Post-Mortem

Protocol Information

Protocol Type Services
Smart Contract Language Solidity
Official Website feg.io/
Protocol Twitter/X @FEGtoken

Market Context at Time of Hack

Token Categories
Memes Solana Ecosystem

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 Operational-security tradecraft (phishing, malware, leaked seed phrases, or insider access) to obtain treasury signing authority
Capital Required Minimal capital - only enough to cover gas while draining the compromised accounts
On-Chain Access Valid signing authority over the compromised wallets / multisig signers, allowing direct transfer of funds or stake authorization
Target Reconnaissance Identification of Fegex's high-value treasury accounts and the authority / multisig structure controlling them
Execution Speed Speed to drain the compromised accounts before the team detects the breach and revokes signing authority or freezes the assets
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? Likely — with a thorough Missing Access Control audit checklist and test coverage
Audited by Audit Report 1 — still lost $900K. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to Fegex, these are the critical security checks that could have prevented this incident (December 2024).

  • Verify all logic paths related to Missing Access Control are guarded by proper access controls and input validation - see the Access Control Attacks attack class for patterns
  • 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.

Free Trial

Security Audit History

Related Attack Classes

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

See all Access Control Attacks examples →

Sources & References

Learn to Prevent the Next Fegex

The Fegex hack is one of many attacks that skilled auditors are trained to detect before deployment. Master real exploit patterns and defense techniques with hands-on Web3 security training.

Recreate exploit patterns safely Free Trial