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

Less than three weeks after North Korea-linked hackers compromised crypto trading firm Drift using social engineering tactics, it appears that hackers with ties to the nation have executed another significant exploit, this time targeting Kelp, a restaking protocol connected to LayerZero's cross-chain infrastructure. This attack suggests that North Korea-linked hackers are adapting their strategies, moving beyond exploiting bugs or stolen credentials to manipulate the fundamental assumptions underlying decentralized systems. The combined impact of these two incidents points to a more organized effort than isolated hacks, as North Korea continues to intensify its attempts 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's a cadence. You cannot patch your way out of a procurement schedule.' More than $500 million was stolen across 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 occurred. As Urbelis noted, 'The security failure is simple: a signed lie is still a lie. Signatures guarantee authorship; they do not guarantee truth.' This exploit highlights a configuration issue where Kelp relied on a single verifier to approve cross-chain messages, a choice made for speed and simplicity but one that 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 pushed back against this recommendation, stating that LayerZero's default setup was to use a single verifier. David Schwed, COO of blockchain security firm SVRN, emphasized, 'If you've identified a configuration as unsafe, don't ship it as an option. Security that depends on everyone reading the documentation and getting it right is not realistic.' The fallout from the exploit has extended beyond Kelp, affecting lending platforms like Aave that accepted impacted assets as collateral, thereby turning a single exploit into a broader stress event. As Schwed explained, 'These assets are 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 attack also reveals a disparity between the marketing of decentralization and its actual implementation. 'A single verifier is not decentralized; it's a centralized decentralized verifier,' Schwed said. Urbelis expanded on this, stating, '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 why Lazarus, a North Korea-linked hacking group, has recently targeted cross-chain and restaking infrastructure, the parts of crypto that move assets between systems or allow them to be reused. These layers are critical but complex, often underlying more visible applications, and they tend to hold large amounts of value, making them attractive targets. As Lazarus adapts, 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.