North Korea's Cryptocurrency Theft Strategies Are Evolving, with DeFi Being Repeatedly Targeted

Less than three weeks after hackers linked to North Korea used social engineering tactics to breach the cryptocurrency trading firm Drift, it appears that hackers tied to the same nation have carried out 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, who are no longer just exploiting bugs or using stolen credentials, but are now manipulating the fundamental assumptions built into decentralized systems. The combined impact of these two incidents points to a more organized effort than a series of isolated hacks, as North Korea continues to escalate 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 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 actually occurred. As Urbelis noted, 'The security failure is simple: a signed lie is still a lie. Signatures guarantee authorship; they do not guarantee truth.' In simpler terms, the system verified who sent the message but not whether the message itself was correct. For security experts, this exploit highlights the issue of exploiting how the system was set up rather than discovering a new hack. David Schwed, COO of blockchain security firm SVRN, emphasized, 'This attack wasn’t about breaking cryptography; it was about exploiting how the system was set up.' A key issue was a configuration choice, with Kelp relying 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 in the ecosystem have pushed back against this recommendation, arguing that LayerZero’s default setup was to have a single verifier. Schwed argued, '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 impact of the exploit has not been limited to Kelp, 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 marketing of decentralization and its actual implementation. As Schwed pointed out, 'A single verifier is not decentralized; it’s a centralized decentralized verifier.' Urbelis broadened this perspective, 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, even systems that appear decentralized can have weak points, especially in less visible layers like data providers or infrastructure, which are increasingly the focus of attackers. This shift may explain why Lazarus, a group linked to North Korea, has recently targeted cross-chain and restaking infrastructure, the parts of the cryptocurrency space 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 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.