
Briefing
On October 16, 2024, the Radiant Capital protocol suffered a sophisticated cyberattack resulting in the loss of approximately $50 million USD from its core lending markets on Arbitrum and BNB Chain. The incident stemmed from a malware injection on the devices of at least three core developers, which enabled the manipulation of transaction data during a routine multi-signature emissions adjustment. This allowed attackers to obtain fraudulent signatures for a transferOwnership action, bypassing both front-end verification and simulation tools, ultimately leading to the unauthorized draining of assets.

Context
Prior to this incident, the DeFi landscape has seen a persistent rise in sophisticated social engineering and supply chain attacks targeting key personnel, often bypassing robust smart contract audits. While multi-signature schemes are designed to enhance security by requiring multiple approvals, the prevailing risk factor lies in the human element and the integrity of the signing environment. This exploit leveraged advanced device-level compromise, highlighting a critical vulnerability class where off-chain attack vectors directly undermine on-chain security controls.

Analysis
The attack began with a social engineering tactic on September 11, 2024, where a Radiant developer received a malicious zipped PDF via Telegram, masquerading as a former contractor’s job opportunity. This delivered INLETDRIFT malware, establishing a persistent macOS backdoor on compromised devices. During a subsequent routine multi-signature emissions adjustment, the malware manipulated the display within the Safe{Wallet} (Gnosis Safe) front-end and Tenderly simulations, presenting legitimate transaction data while simultaneously sending malicious transferOwnership transactions to hardware wallets for signing. This allowed the attackers, identified as the North Korean threat actor UNC4736, to secure the necessary three-of-eleven multi-signature approvals, seize control of the Pool Provider contract, and deploy malicious versions to drain funds from the protocol’s core markets on Arbitrum and BNB Chain.

Parameters
- Protocol Targeted ∞ Radiant Capital
- Date of Exploit ∞ October 16, 2024
- Attack Vector ∞ Malware-driven device compromise and transaction spoofing
- Financial Impact ∞ $50 Million USD
- Affected Blockchains ∞ Arbitrum, BNB Chain
- Threat Actor ∞ UNC4736 (North Korea-aligned)
- Initial Compromise ∞ Social engineering via malicious zipped PDF

Outlook
Immediate mitigation for users involved revoking all approvals on Arbitrum, BSC, Ethereum, and Base. This incident underscores the critical need for enhanced security practices beyond smart contract audits, emphasizing device-level integrity and robust transaction verification mechanisms, especially when interacting with multi-signature wallets. Protocols must consider implementing stricter controls for developer environments, integrating advanced endpoint detection, and educating teams on sophisticated social engineering tactics. This event will likely accelerate the adoption of trustless transaction signing solutions and hardware-isolated signing environments to prevent similar device-level compromises from undermining on-chain security.