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, this time targeting Kelp, a restaking protocol integrated into LayerZero's cross-chain infrastructure. This attack suggests that North Korea-linked hackers are adapting their methods, no longer just seeking out vulnerabilities or stolen credentials, but instead exploiting fundamental assumptions built into decentralized systems. The combined impact of these incidents points to a more organized effort by North Korea to intercept 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 through the Drift and Kelp exploits in just over two weeks. The Kelp breach did not involve breaking encryption or cracking keys; instead, attackers manipulated the data feeding into the system, forcing it to rely on compromised inputs and approve transactions that never actually occurred. 'The security failure is simple: a signed lie is still a lie,' Urbelis noted. 'Signatures guarantee authorship; they do not guarantee truth.' In simpler terms, the system verified who sent the message but not whether the message itself was accurate. For security experts, this exploit highlights the issue of exploiting how the system was set up rather than discovering a new hack. David Schwed, COO of blockchain security firm SVRN, stated, 'This attack wasn’t about breaking cryptography; it was about exploiting how the system was set up.' A key issue was the configuration choice of 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 incident, LayerZero 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 on this recommendation, 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 has not been limited to Kelp, as its assets are used across multiple platforms, leading to problems spreading across the ecosystem. 'These assets are a chain of IOUs,' Schwed explained. '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, with lending platforms like Aave that accepted the impacted assets as collateral now dealing with losses. The attack also reveals a gap between the marketing of decentralization and its actual implementation. 'A single verifier is not decentralized,' Schwed said. '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 even systems that appear decentralized can have weak points, particularly in less visible layers like data providers or infrastructure, where attackers are increasingly focusing their efforts. This shift might explain the recent targeting by Lazarus, a group that 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 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; it showed how exposed the ecosystem remains to familiar ones, especially when security is treated as a recommendation rather than a requirement. As attackers move faster, this gap is becoming both easier to exploit and far more expensive to ignore.