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

Less than three weeks after hackers linked to North Korea used social engineering to breach the crypto trading firm Drift, another significant exploit has been carried out against Kelp, a restaking protocol connected to LayerZero's cross-chain infrastructure. This attack signifies an evolution in the tactics employed by North Korea-linked hackers, as they now exploit fundamental assumptions built into decentralized systems, rather than merely seeking out bugs or stolen credentials. The cumulative effect of these incidents suggests a more organized effort by North Korea 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 in just over two weeks across the Drift and Kelp exploits. 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 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 highlights a critical issue with the system's configuration, which relied on a single verifier to approve cross-chain messages, a choice that, while faster and simpler to set up, 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 in the ecosystem 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 repercussions of the exploit have 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. This situation exposes a disparity 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 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 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 in targeting may explain why Lazarus, a group linked to North Korea, has begun targeting cross-chain and restaking infrastructure, the parts of the crypto sector 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.