Briefing
An advanced phishing campaign successfully targeted a 2-of-4 Safe multi-signature wallet, orchestrating the unauthorized transfer of digital assets. The attacker exploited the Safe Multi Send mechanism, employing a meticulously crafted, fake Etherscan-verified contract to obscure a malicious approval within a seemingly routine transaction. This intricate social engineering attack resulted in the exfiltration of $3.047 million in USDC, which the perpetrator subsequently routed through Tornado Cash to obfuscate the funds’ origin.
Context
Prior to this incident, the prevailing threat landscape included increasing sophistication in phishing attacks, often targeting user approvals and leveraging trust in verified on-chain entities. The inherent complexity of multi-signature wallet interactions and the reliance on visual inspection for contract addresses created a fertile attack surface. Attackers frequently exploited the difficulty users face in discerning legitimate contract interactions from malicious ones, particularly when complex transaction bundles are involved.
Analysis
The incident’s technical mechanics involved the attacker deploying a counterfeit contract weeks in advance, programmed with legitimate-looking batch payment functions and achieving Etherscan verification. The core system compromised was the user’s trust and the Safe Multi Send mechanism’s ability to bundle transactions, which the attacker leveraged to disguise a critical malicious approval. The attacker initiated two consecutive transactions where the victim approved transfers to an address designed to mimic a legitimate recipient, mirroring its first and last characters. This deceptive contract, combined with the Request Finance app interface for execution, allowed the malicious approval to execute under the guise of a standard operation, thereby circumventing the victim’s scrutiny and enabling the asset drain.
Parameters
- Exploited Protocol/Wallet ∞ 2-of-4 Safe Multi-signature Wallet
- Attack Vector ∞ Sophisticated Phishing via Malicious Contract Mimicry and Safe Multi Send
- Financial Impact ∞ $3.047 Million USDC
- Blockchain Affected ∞ Ethereum
- Key Forensic Detail ∞ Funds bridged to Ethereum, then laundered via Tornado Cash
- Initial Detection ∞ ZachXBT on September 11, 2025
- Exploit Mechanism ∞ Fake Etherscan-verified contract with mirrored address characters
Outlook
Immediate mitigation steps for users include rigorous verification of all transaction details, even within seemingly legitimate interfaces, and a heightened awareness of contract address spoofing. This incident underscores the urgent need for enhanced wallet security features that provide clearer, human-readable breakdowns of complex transaction approvals. The broader ecosystem faces a contagion risk if similar sophisticated phishing techniques are not robustly countered, potentially leading to new security best practices centered on advanced transaction simulation and pre-signing analysis tools to detect hidden malicious approvals.
Verdict
This incident decisively confirms the escalating threat of highly sophisticated social engineering tactics targeting the weakest link in digital asset security ∞ human vigilance.
Signal Acquired from ∞ cryptoslate.com
