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

Less than three weeks after hackers linked to North Korea used social engineering to breach the cryptocurrency trading firm Drift, another significant exploit has been attributed to the nation, this time targeting Kelp, a restaking protocol connected to LayerZero's cross-chain infrastructure. This attack signals an evolution in the tactics employed by North Korean hackers, as they move beyond exploiting bugs or stolen credentials to manipulating the foundational assumptions of decentralized systems. The combined incidents of Drift and Kelp suggest a more organized effort by North Korea to siphon funds from the cryptocurrency sector, rather than isolated hacks. 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 stolen across these two exploits in just over two weeks, highlighting the scale and efficiency of these operations. The Kelp breach did not involve breaking encryption or cracking keys; instead, attackers manipulated the data input into the system, forcing it to rely on compromised inputs and approve non-existent transactions. This exploit underscores the issue of security relying on the integrity of the input data, rather than just the identity of the sender. 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 on Kelp exploited a configuration choice that relied on a single verifier for cross-chain messages, a setup that, while faster and simpler, 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 have argued that LayerZero's default setup was to use a single verifier, pointing to a gap between the security expectations and the actual implementation. The impact of the Kelp exploit has not been contained, as the assets involved 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. This situation highlights the interconnected nature of DeFi systems, where the strength of the chain is only as strong as the controls on each link. When one link breaks, others are affected, turning a single exploit into a broader crisis. The attack also reveals a discrepancy between the marketing of decentralization and its actual implementation. As Schwed pointed out, 'A single verifier is not decentralized; it's a centralized decentralized verifier.' Urbelis further emphasized, '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 systems appearing to be decentralized can have centralized weak points, especially 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, critical for moving assets between systems or allowing them to be reused, are complex, often less visible, and tend to hold large amounts of value, making them attractive targets. As Lazarus adapts its tactics, the biggest risk may not be unknown vulnerabilities but known ones that are not fully addressed. The Kelp exploit did not introduce a new kind of weakness but showed how exposed the ecosystem remains to familiar ones, especially when security is treated as a recommendation rather than a requirement. This gap is becoming both easier to exploit and far more expensive to ignore, as attackers move faster and the financial impact of these exploits grows.