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

Barely three weeks after hackers linked to North Korea used social engineering to breach the crypto trading firm Drift, another significant exploit has been attributed to the nation, this time targeting Kelp, a restaking protocol integrated into LayerZero's cross-chain infrastructure. This latest attack suggests an advancement in the tactics employed by North Korea-linked hackers, who are now exploiting fundamental assumptions in decentralized systems, rather than merely seeking out bugs or stolen credentials. The cumulative effect of these incidents points to a more organized effort by North Korea 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.' The Drift and Kelp exploits collectively resulted in the theft of over $500 million in just over two weeks. The Kelp breach did not involve breaking encryption or cracking keys; instead, attackers manipulated the data fed into the system, forcing it to rely on compromised inputs and approve transactions that did not actually occur. As Urbelis noted, 'A signed lie is still a lie. Signatures guarantee authorship; they do not guarantee truth.' This exploit highlights a security failure stemming from the system's design, where the focus was on verifying the sender rather than the correctness of the message itself. The attack on Kelp was not about breaking cryptography but about exploiting the system's configuration. A key issue was the use of 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, arguing that LayerZero's default setup was to have 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 impact of the exploit has not been limited to Kelp, as its assets are used across multiple platforms, causing problems to spread. 'These assets are a chain of IOUs,' Schwed said, 'and the chain is only as strong as the controls on each link.' When one link breaks, others are affected, turning a single exploit into a wider stress event. For instance, lending platforms like Aave that 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. 'A single verifier is not decentralized,' Schwed pointed out. 'It's a centralized decentralized verifier.' Urbelis further clarified, '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 appearing decentralized can have weak points, especially 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, which has begun focusing on 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 sitting underneath 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.