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, it appears that hackers with ties to the nation have carried out another significant exploit, this time targeting Kelp. The attack on Kelp, a restaking protocol integrated into LayerZero's cross-chain infrastructure, suggests that North Korea-linked hackers are adapting their methods, no longer just seeking out bugs or stolen credentials, but also exploiting the fundamental assumptions built into decentralized systems. 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 cryptocurrency sector. This is not a series of isolated incidents, but rather a sustained campaign. 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 breach 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 thus approving transactions that never actually occurred. This exploit highlights a simple security failure: a signed lie is still a lie. Signatures guarantee authorship but do not guarantee truth. In essence, the system checked who sent the message, not whether the message itself was correct. For security experts, this exploit is less about a new, clever hack and more about exploiting how the system was set up. 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 a configuration choice: Kelp relied on a single verifier to approve cross-chain messages, which, although faster and simpler to set up, removes a critical safety layer. Following the exploit, LayerZero recommended using multiple independent verifiers to approve transactions, similar to requiring multiple signatures on a bank transfer. However, some in the ecosystem have pushed back on this recommendation, 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 limited to Kelp itself, 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. This situation highlights that these assets are essentially a chain of IOUs, and the chain is only as strong as the controls on each link. When one link breaks, others are affected. The exploit also exposes a gap 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 expanded on this, saying, '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.' In practice, this means that even systems that appear decentralized can have weak points, particularly in less visible layers like 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, which are critical but complex and often under visible applications, suggests a shift in strategy. These layers are attractive targets because they hold large amounts of value and are harder to monitor and easier to misconfigure. As Lazarus continues to adapt, 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; it showed how exposed the ecosystem remains to familiar ones, especially when security is treated as a recommendation rather than a requirement. And as attackers move faster, this gap is becoming both easier to exploit and far more expensive to ignore.