North Korea's Cyber 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 connected to LayerZero's cross-chain infrastructure. This attack signifies an evolution in the tactics employed by North Korean hackers, as they are no longer just seeking out vulnerabilities or stolen credentials, but are now exploiting the fundamental assumptions underlying decentralized systems. The combined impact of these two incidents suggests a more organized effort by North Korea to siphon 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.' More than $500 million was stolen across the Drift and Kelp exploits in just over two weeks. The Kelp exploit 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 non-existent transactions. 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 the sender's identity but not the message's accuracy, making this exploit more about manipulating the system's setup than discovering a new hack. David Schwed, COO of blockchain security firm SVRN, agrees, stating, 'This attack wasn’t about breaking cryptography. It was about exploiting how the system was set up.' A key issue was Kelp's reliance on a single verifier to approve cross-chain messages, a configuration choice that, while faster and simpler, 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 have pushed back against this, arguing that LayerZero's default setup was to use a single verifier. Schwed emphasizes, '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 a wider stress event. Lending platforms like Aave, which accepted the affected assets as collateral, are now dealing with losses. The incident also highlights the gap between the marketing of decentralization and its actual implementation. As Schwed points out, 'A single verifier is not decentralized. It’s a centralized decentralized verifier.' Urbelis expands 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 even seemingly decentralized systems can have weak points, particularly in less visible layers such as data providers or infrastructure, which are increasingly the focus of attackers. This shift might explain why Lazarus, a group linked to North Korea, has begun targeting 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 and often hold large amounts of value, making them attractive targets. As Lazarus adapts, 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.