Incident Overview
The lack of validation of assets in the swap function contributed to the attacker taking advantage of this vulnerability, and to pull off a flash loan attack.
Attacker address (BSC): https://bscscan.com/address/0x73b359d5…e9fF7C
Attacker address (ETH): https://etherscan.io/address/0x73b359d5…e9fF7C
Attacker contract address (BSC): https://bscscan.com/address/0x9a843bb1…82f445
Attacker contract address (ETH):https://etherscan.io/address/0x9a843bb1…82f445
One of the attacker transaction on BSC: https://bscscan.com/tx/0xe4b03c4a…e1355b
Attacker transaction on ETH: https://etherscan.io/tx/0x03bd0cfc…07188f
Total losses: $1.5M
Incident Report
Protocol Information
Market Context at Time of Hack
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.
What Auditors Should Check
If you're auditing a protocol with similar architecture to FEGtoken, these are the critical security checks that could have prevented this incident (May 2022).
- Verify all logic paths related to Flash Loan Attack are guarded by proper access controls and input validation - see the Flash Loans 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 TrialSecurity Audit History
- Solidity Finance Report
Related Attack Classes
The technique used in this hack maps to these vulnerability classes in our security curriculum:
Sources & References
-
01
Source 1 https://fegtoken.com/
Learn to Prevent the Next FEGtoken
The FEGtoken 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.