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

Less than three weeks after North Korea-linked hackers used social engineering to breach the crypto trading firm Drift, hackers associated with the nation appear to have executed another significant exploit, this time targeting Kelp, a restaking protocol connected to LayerZero's cross-chain infrastructure. This attack suggests an evolution in the tactics employed by North Korea-linked hackers, shifting from merely exploiting bugs or using stolen credentials to manipulating the fundamental assumptions underlying decentralized systems. The combined impact of these incidents points to a more organized effort than isolated hacks, as North Korea intensifies its attempts to hijack 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 off through the Drift and Kelp exploits in just over two weeks. 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 approve transactions that never actually occurred. 'The security failure is simple: a signed lie is still a lie,' Urbelis noted. 'Signatures guarantee authorship; they do not guarantee truth.' In simpler terms, the system verified the sender of the message but not the accuracy of the message itself. For security experts, this exploit highlights the manipulation of the system's setup rather than the discovery of a novel hack. David Schwed, COO of blockchain security firm SVRN, stated, '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, a setup that is faster and simpler but 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 against this recommendation, arguing 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 exploit has not been contained to Kelp; since its assets are used across multiple platforms, the problems have spread. 'These assets are a chain of IOUs,' Schwed explained. 'And the chain is only as strong as the controls on each link.' When one link breaks, others are affected. In this case, lending platforms like Aave that accepted the impacted assets as collateral are now dealing with losses, turning a single exploit into a broader stress event. The attack also exposes a discrepancy between how decentralization is marketed and how it actually functions. 'A single verifier is not decentralized,' Schwed said. 'It’s a centralized decentralized verifier.' Urbelis offered a broader perspective: '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 such as data providers or infrastructure, which are increasingly the focus of attackers. This shift may explain the recent targeting by the Lazarus group. The group has begun focusing on cross-chain and restaking infrastructure, Urbelis said, the parts of the cryptocurrency space that move assets between systems or allow them to be reused. These layers are critical but complex, often sitting beneath more visible applications, and they tend to hold large amounts of value, making them attractive targets. 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 demonstrated how exposed the ecosystem remains to familiar vulnerabilities, 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.