North Korea's Cryptocurrency Theft Tactics Are Evolving, with DeFi Being a Prime Target

Less than three weeks after hackers with ties to North Korea used social engineering to breach the crypto trading firm Drift, another significant exploit was carried out against Kelp, a restaking protocol integrated into LayerZero's cross-chain infrastructure. This attack suggests an evolution in the tactics of North Korea-linked hackers, who are no longer just exploiting bugs or stolen credentials but are now manipulating the fundamental assumptions built into decentralized systems. The combined impact of these incidents points 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.' More than $500 million was siphoned across the Drift and Kelp exploits in just over two weeks, highlighting the escalating efforts by North Korea to hijack funds from the crypto sector. The Kelp exploit did not involve breaking encryption or cracking keys; instead, attackers manipulated the data feeding into the system, forcing it to rely on compromised inputs and approve transactions that never occurred. This security failure is attributed to the system's design, where it checked the sender's identity but not the truthfulness of the message. For security experts, this exploit is less about a novel hack and more about exploiting the system's setup. David Schwed, COO of blockchain security firm SVRN, noted, 'This attack wasn’t about breaking cryptography; it was about exploiting how the system was set up.' A key issue was the configuration choice of relying on a single verifier to approve cross-chain messages, which, although faster and simpler to set up, removes 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 in the ecosystem have pushed back, stating that LayerZero’s default setup was to have a single verifier. Schwed emphasized, 'If you’ve identified a configuration as unsafe, don’t ship it as an option. Security that depends on everyone reading the docs and getting it right is not realistic.' The fallout from the Kelp exploit has not been contained, as its assets are used across multiple platforms, leading to a wider stress event. Lending platforms like Aave, which accepted the impacted assets as collateral, are now dealing with losses. The attack also exposes a gap between the marketed concept of decentralization and its actual implementation. As Urbelis put it, '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 means that even seemingly decentralized systems can have weak points, particularly in less visible layers such as data providers or infrastructure, which are increasingly 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 are critical but complex and often hold large amounts of value, making them attractive targets. The biggest risk may not be unknown vulnerabilities but known ones that are not fully addressed, as the Kelp exploit demonstrated how exposed the ecosystem remains to familiar weaknesses, especially when security is treated as a recommendation rather than a requirement.