North Korea's Cryptocurrency Theft Strategy Expands, Targeting DeFi

Less than three weeks after hackers linked to North Korea used social engineering to breach the crypto trading firm Drift, another major exploit occurred with Kelp, a restaking protocol connected to LayerZero's cross-chain infrastructure. This attack suggests an evolution in the tactics of North Korea-linked hackers, who are now exploiting the fundamental assumptions of decentralized systems, rather than just looking for bugs or stolen credentials. The combined incidents of the Drift and Kelp exploits, which resulted in the theft of over $500 million in just over two weeks, point to a more organized effort by North Korea to hijack funds from the crypto sector. According to Alexander Urbelis, chief information security officer and general counsel at ENS Labs, 'This is not a series of incidents; it is a cadence. You cannot patch your way out of a procurement schedule.' The Kelp exploit did not involve breaking encryption or cracking keys but rather manipulated the data feeding into the system, forcing it to rely on compromised inputs and approve transactions that never actually occurred. As David Schwed, COO of blockchain security firm SVRN, noted, 'The security failure is simple: a signed lie is still a lie. Signatures guarantee authorship; they do not guarantee truth.' The attack highlights a configuration issue where Kelp relied on a single verifier to approve cross-chain messages, a choice that, while faster and simpler to set up, removes a critical safety layer. In response, LayerZero has recommended using multiple independent verifiers to approve transactions. The fallout from the exploit has extended beyond Kelp, affecting lending platforms like Aave that accepted the impacted assets as collateral, thereby turning a single exploit into a wider stress event. The incident also exposes a gap between the marketing of decentralization and its actual implementation, with Schwed pointing out, 'A single verifier is not decentralized. It's a centralized decentralized verifier.' Urbelis further emphasizes, 'Decentralization is not a property a system has. It is a series of choices. And the stack is only as strong as its most centralized layer.' This shift in targeting cross-chain and restaking infrastructure, which are critical but complex and often less visible, may explain the recent focus of Lazarus, a group linked to North Korea. As these layers hold large amounts of value and are increasingly targeted, the biggest risk may not be unknown vulnerabilities but known ones that are not fully addressed. The Kelp exploit demonstrates how exposed the ecosystem remains to familiar weaknesses, especially when security is treated as a recommendation rather than a requirement.