North Korea's Cryptocurrency Hacking Strategy Expands, Targeting DeFi

Less than three weeks after hackers linked to North Korea used social engineering to breach crypto trading firm Drift, another major exploit has been carried out against Kelp, a restaking protocol connected to LayerZero's cross-chain infrastructure. This attack suggests that North Korea-linked hackers are evolving their tactics, exploiting not just vulnerabilities but the fundamental assumptions underlying decentralized systems. The combined incidents of the Drift and Kelp exploits, which together resulted in the theft of over $500 million in just over two weeks, point to a more organized effort by North Korea to siphon funds from the cryptocurrency 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 but rather manipulating the data fed into the system, forcing it to rely on compromised inputs and approve non-existent transactions. As David Schwed, COO of blockchain security firm SVRN, noted, 'The security failure is simple: a signed lie is still a lie.' This highlights that the system's security failure was due to its design, which checked the sender's identity but not the truth of the message. The exploit was facilitated by Kelp's reliance on a single verifier to approve cross-chain messages, a configuration choice that removed a critical safety layer. In response, LayerZero has recommended using multiple independent verifiers to approve transactions, akin to requiring multiple signatures on a bank transfer. However, some have argued that LayerZero's default setup was to use a single verifier, emphasizing the need for more robust security configurations. The fallout from the Kelp exploit has extended beyond the platform itself, affecting lending platforms like Aave that accepted the impacted assets as collateral, thereby turning a single exploit into a broader stress event. The incident also exposes a disconnect 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 emphasized that '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 highlights the importance of considering the entire stack's security, especially in less visible layers such as data providers or infrastructure, which are increasingly becoming the focus of attackers. The recent targeting by Lazarus, a group linked to North Korea, of cross-chain and restaking infrastructure, underscores this shift. These layers, critical for moving assets between systems or allowing them to be reused, hold significant value and are complex, making them attractive targets. As the crypto sector continues to evolve, the biggest risk may not be unknown vulnerabilities but known ones that are not fully addressed, with the gap between security recommendations and requirements becoming both easier to exploit and more costly to ignore.