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

Less than three weeks after hackers linked to North Korea used social engineering to breach the cryptocurrency trading firm Drift, another significant exploit was carried out against 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 now exploiting fundamental assumptions built into decentralized systems, rather than just looking for bugs or stolen credentials. The combined incidents of Drift and Kelp exploits, which resulted in the theft of over $500 million in just over two weeks, indicate a more organized effort by North Korea to hijack funds from the crypto 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.' The Kelp exploit 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 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 means the system checked who sent the message but not whether the message itself was correct, making this exploit more about manipulating the system's setup than about breaking cryptography. David Schwed, COO of blockchain security firm SVRN, agreed, stating, '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, which, although faster and simpler to set up, removes a critical safety layer. Following the exploit, LayerZero recommended using multiple independent verifiers to approve transactions, similar to requiring multiple signatures on a bank transfer. However, some have pushed back on this framing, 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 impact of the Kelp exploit has not been limited to Kelp itself, 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. This highlights the interconnected nature of DeFi systems, where assets are essentially 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 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, this means 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. The recent targeting by the Lazarus group, which has begun focusing on cross-chain and restaking infrastructure, underscores this shift. 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. If earlier waves of crypto hacks focused on exchanges or obvious code flaws, recent activity suggests a move toward what could be called the industry’s plumbing, the systems that connect everything together but are harder to monitor and easier to misconfigure. 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.