Briefing
A sophisticated phishing attack successfully compromised a 2-of-4 Safe multi-signature wallet, resulting in the unauthorized exfiltration of $3.047 million in USDC. The incident leveraged a fake Etherscan-verified contract and the Safe Multi Send mechanism to obscure malicious transaction approvals. This exploit underscores the critical need for heightened vigilance against advanced social engineering tactics, even within robust security architectures. The attacker rapidly converted the stolen USDC to Ethereum before channeling the funds through Tornado Cash, complicating recovery efforts.
Context
The prevailing threat landscape in decentralized finance consistently features advanced social engineering as a primary attack vector, targeting human elements within secure systems. Prior to this incident, a known risk factor involved attackers creating convincing but fraudulent smart contracts or interfaces to trick users into granting malicious approvals. This exploit capitalized on the inherent trust users place in verified contract interfaces and the complexity of reviewing granular transaction details within multi-operation signatures.
Analysis
The incident’s technical mechanics involved a multi-stage attack. First, the threat actor deployed a fake, Etherscan-verified contract weeks in advance, programming it with legitimate-looking “batch payment” functions. The attack then exploited the Safe Multi Send mechanism within the Request Finance app interface, disguising an abnormal approval inside what appeared to be a routine transaction.
The attacker crafted the malicious contract address to mirror the legitimate recipient’s address, using identical first and last characters. This obfuscation tactic bypassed the victim’s scrutiny, leading to the approval of two consecutive malicious transactions that ultimately drained $3.047 million in USDC from the multi-signature wallet.
Parameters
- Targeted Entity → Unidentified crypto investor’s 2-of-4 Safe multi-signature wallet
- Attack Vector → Sophisticated Phishing via Malicious Contract Approval
- Financial Impact → $3.047 Million USD (USDC)
- Affected Blockchain → Ethereum
- Obfuscation Method → Fake Etherscan-verified contract, Safe Multi Send mechanism, Address Mimicry
- Exfiltration Route → USDC swapped to Ethereum, funneled to Tornado Cash
- Incident Source → Request Finance app interface (compromised interaction)
Outlook
Immediate mitigation for users requires extreme caution when approving transactions, demanding meticulous review of all contract details, even those appearing routine. Protocols must enhance their front-end security to detect and warn against suspicious contract interactions, particularly those involving multi-send mechanisms. This incident will likely drive new best practices in transaction simulation tools and user education, emphasizing the need for independent verification beyond basic Etherscan checks. The continued use of privacy protocols like Tornado Cash by threat actors highlights an ongoing challenge in asset tracing and recovery.
Verdict
This incident decisively confirms that even robust multi-signature security is vulnerable to advanced social engineering and contract mimicry, necessitating a systemic shift towards enhanced user-side verification and protocol-level threat intelligence.
Signal Acquired from → cryptoslate.com
