User Loses $440K in USDC After Signing Malicious Permit in Phishing Attack

• A single malicious permit signature resulted in a $440,358 USDC loss for one user on December 8, 2025.

• Phishing losses surged 137% in November 2025, totaling $7.77 million across over 6,000 victims despite fewer incidents.

• Scammers target high-value wallets, with the largest single permit scam hitting $1.22 million, according to Scam Sniffer’s report.

Discover how permit scams in crypto drained $440K from one victim—learn the risks, prevention tips, and rising trends in phishing attacks for safer wallet management today.

What are permit scams in crypto?

Permit scams in crypto are deceptive tactics where attackers trick users into approving unauthorized access to their digital assets through seemingly legitimate transaction signatures. These scams leverage Ethereum’s permit function, designed to streamline token approvals, but malicious actors exploit it to drain funds instantly. In a recent case reported by Scam Sniffer on December 8, 2025, one user lost $440,358 in USDC after signing a fake permit, underscoring the growing threat amid a 137% rise in phishing losses to $7.77 million in November 2025.

How do permit-based phishing attacks work?

Permit-based phishing attacks begin with scammers creating fake decentralized applications or websites that mimic trusted platforms. Users are prompted to connect their wallets and sign a “permit” transaction, which appears routine but actually delegates unlimited spending rights to the attacker. This exploits the ERC-20 standard’s permit feature, allowing off-chain approvals to reduce gas fees and simplify interactions.

Once signed, the attacker can execute transfers without further user input. For instance, Scam Sniffer’s analysis revealed that in November 2025, such scams affected over 6,000 victims, with losses jumping 137% from October despite a 42% drop in victim numbers. This indicates a shift toward “whale hunting,” targeting larger holdings for bigger payouts—the largest recorded permit scam stole $1.22 million.

Experts highlight the subtlety of these attacks. Tara Annison, head of product at Twinstake, explained that scammers often disguise the permit as part of free airdrops, fake project pages, or security checks. “The success of these types of scams relies on you signing something that you don’t quite realize what it will do,” she noted. “It’s all about the human vulnerability and taking advantage of people’s eagerness.”

Annison further detailed how attackers can either drain funds immediately in a single transaction or set long-term access, lying dormant until more assets are added. This dormancy makes detection harder, as the permit’s deadline can extend far into the future. According to Scam Sniffer’s monthly report, these methods have intensified, with individual losses growing significantly even as overall attack volume decreases.

Supporting data from blockchain analytics shows Ethereum remains the primary battlefield, but similar vulnerabilities exist across EVM-compatible chains. Wallet providers like MetaMask have introduced safeguards, such as transaction simulators that decode intent into plain language, yet scammers adapt by spoofing contract names or hiding fields in the signature request.

Frequently Asked Questions

What should you do if you suspect you’ve fallen victim to a permit scam in crypto?

If you suspect a permit scam in crypto, immediately disconnect your wallet from any suspicious sites and revoke all approvals using tools like Etherscan’s token approval checker. Contact your wallet provider for support, monitor your accounts closely, and report the incident to platforms like Scam Sniffer. Recovery is rare, but swift action can prevent further losses—act within hours to mitigate damage.

How can you spot and avoid malicious permit signatures in cryptocurrency transactions?

To spot malicious permit signatures in cryptocurrency transactions, always review the transaction details before signing: check the contract address against known legitimate ones and look for unlimited approval amounts. Use wallets with built-in warnings, like MetaMask’s risk alerts, and avoid connecting to unverified dApps. Harry Donnelly, founder and CEO of Circuit, advises verifying sender addresses and ensuring they match your intended protocol to block theft attempts effectively.

Key Takeaways

• Permit scams exploit trust: They mimic legitimate approvals to grant attackers token access, as seen in the $440K USDC loss reported by Scam Sniffer.
• Losses are escalating: November 2025 phishing totals hit $7.77 million, up 137% from October, with focus on high-value targets yielding hits up to $1.22 million.
• Vigilance is essential: Double-check signatures, use protective wallet features, and revoke unnecessary approvals regularly to safeguard your crypto assets.

Conclusion

Permit scams in crypto represent a persistent and evolving threat, as evidenced by the $440,000 USDC theft and the broader surge in phishing losses to $7.77 million in November 2025. By understanding how these attacks weaponize Ethereum’s permit function and heeding advice from experts like Tara Annison of Twinstake and Harry Donnelly of Circuit, users can bolster their defenses through careful verification and advanced wallet tools. As the crypto ecosystem matures, staying informed and proactive will be crucial—implement these strategies today to protect your investments and contribute to a more secure decentralized future.

The incident highlights the need for ongoing education in the space. Martin Derka, co-founder and technical lead at Zircuit Finance, emphasized that recovery from such phishing attacks is “basically zero,” as scammers operate anonymously and prioritize quick drains. Prevention remains the strongest shield: always scrutinize what you sign, leverage improved dApp interfaces for transparency, and avoid haste in wallet connections.

Broader trends show scammers refining their tactics, from immediate smash-and-grab transfers to stealthy long-term access. Scam Sniffer’s report underscores a 42% drop in victims but massive per-incident losses, signaling sophisticated targeting. Wallet innovations, such as MetaMask’s human-readable translations and high-risk warnings, offer hope, but user awareness is irreplaceable.

In this landscape, authoritative sources like Scam Sniffer provide vital tracking, revealing patterns without speculation. Their December 8, 2025, alert on the $440,358 USDC loss serves as a stark reminder. For those navigating crypto, integrating these insights into daily practices can avert disaster and foster safer participation.