USDC Permit Signature Phishing Hack

TOTAL LOST $1.8M
Medium Phishing

Summarize with AI

ChatGPT Perplexity Claude Grok
Affected Chain 2026 Incident surface
Recovered - No recovery reported
All-Time Rank #696 By amount stolen
Protocol Type Exploit/Phishing Target category

Incident Overview

Quick Summary

On March 16, 2026, a victim lost $1.76M USDC after signing a malicious Permit signature to phishing contract 0x9F68523e…4FE17E. The stolen funds were converted to 769.19 ETH and distributed across three attacker wallets.

Details of the Exploit

The victim interacted with a phishing website or malicious dApp that presented a seemingly legitimate Permit signature request. When the victim signed the approval, they unknowingly granted the attacker's contract unlimited spending rights to their USDC balance. The malicious contract immediately drained the entire $1.76M USDC balance. The attacker then swapped the stolen USDC for ETH and split the proceeds across three separate wallets to complicate tracking.

Blockchain Data Reference

Tx:

https://etherscan.io/tx/0xfd7417af…f5a642

Victim: https://etherscan.io/address/0x051bb76f…9ab664

This is classified as a Phishing Attacks . Compare similar hacks →

Incident Report

Protocol / Project USDC Permit Signature Phishing
Date of Incident
Attack Technique Phishing
Classification Other
Primary Source View Post-Mortem

Protocol Information

Protocol Type Exploit/Phishing
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 phishing and Solidity and EVM internals
Capital Required Seed capital to cover gas and initial position setup
On-Chain Access Ability to interact with smart contracts and deploy a custom exploit contract
Protocol Analysis Identification of the exploitable vulnerability in USDC Permit Signature Phishing's contract logic - root cause: other
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? Likely — with a thorough Phishing audit checklist and test coverage

If you're auditing a protocol with similar architecture to USDC Permit Signature Phishing, these are the critical security checks that could have prevented this incident (March 2026).

  • Verify all logic paths related to Phishing are guarded by proper access controls and input validation - see the Phishing 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.

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Related Attack Classes

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

See all Phishing Attacks examples →

Phishing Attacks

Sources & References

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