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

Barely three weeks after North Korea-linked hackers employed social engineering tactics to breach the cryptocurrency trading firm Drift, hackers with ties to the nation seem to have successfully carried out another significant exploit, this time targeting Kelp, a restaking protocol integrated into LayerZero's cross-chain infrastructure. This attack signals an evolution in the tactics used by North Korea-linked hackers, as they are no longer just searching for vulnerabilities or stolen credentials but are instead exploiting fundamental assumptions built into decentralized systems. The combined impact of these incidents suggests a more organized approach than isolated hacking attempts, as North Korea continues to intensify its efforts 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 is 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 was particularly notable for how it was carried out, not by breaking encryption or cracking keys, but by manipulating the data fed into the system, forcing it to rely on compromised inputs and thus approving 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.' This exploit highlights a critical issue with how the system was set up, particularly its reliance on a single verifier to approve cross-chain messages, a configuration choice that, while faster and simpler, removes a crucial 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, 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 docs and getting it right is not realistic.' The aftermath of the exploit has not been contained to Kelp, as its assets are utilized across multiple platforms, leading to a ripple effect where problems can spread. 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, as seen with lending platforms like Aave that accepted the impacted assets as collateral, now dealing with losses and turning a single exploit into a broader stress event. The attack also reveals a discrepancy between the marketing of decentralization and its actual operation. As Schwed pointed out, 'A single verifier is not decentralized. It's a centralized decentralized verifier.' 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, 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 of hackers, has begun targeting 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 but 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.