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

Barely three weeks after hackers linked to North Korea used social engineering to breach the cryptocurrency trading firm Drift, another significant exploit has been uncovered, 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 now targeting the fundamental assumptions underlying decentralized systems, rather than merely seeking out vulnerabilities or stolen credentials. The combined impact of these incidents points to a more organized effort by North Korea to commandeer funds from the crypto sector, rather than a series of isolated breaches. 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 total losses from the Drift and Kelp exploits exceed $500 million, accumulated over just two weeks. The nature of the Kelp breach is noteworthy, as it did not involve cracking encryption or breaking keys. Instead, the attackers manipulated the data feeding into the system, forcing it to rely on compromised inputs and thereby approving transactions that did not actually occur. As Urbelis noted, 'The security failure is simple: a signed lie is still a lie. Signatures guarantee authorship; they do not guarantee truth.' In essence, the system verified the sender of the message but not the message's accuracy itself. This distinction makes the attack less about introducing a novel hacking technique and more about exploiting the system's setup. David Schwed, COO of blockchain security firm SVRN, concurred, stating, 'This attack wasn’t about breaking cryptography. It was about exploiting how the system was set up.' A key issue identified was a configuration choice, where Kelp relied on a single verifier to approve cross-chain messages. This approach, while faster and simpler to implement, 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 use 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 repercussions of the exploit have not been contained to Kelp, as its assets are utilized across multiple platforms, leading to a broader stress event. As 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 is compromised, others are affected, leading to lending platforms like Aave, which accepted the impacted assets as collateral, now facing losses. The attack also highlights a disparity between the marketing of decentralization and its actual implementation. Schwed pointed out, 'A single verifier is not decentralized. It’s a centralized decentralized verifier.' Urbelis expanded on this, saying, '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 may explain the recent targeting by Lazarus, a group that has begun focusing on cross-chain and restaking infrastructure, the parts of crypto that facilitate the movement of assets between systems or allow them to be reused. These layers, while critical and complex, often sit beneath more visible applications and tend to hold significant value, making them attractive targets. If earlier waves of crypto hacks focused on exchanges or obvious code flaws, recent activity suggests a move toward targeting the industry’s underlying infrastructure, 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 demonstrated how exposed the ecosystem remains to familiar vulnerabilities, 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.