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

Less than three weeks after hackers linked to North Korea employed 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 suggests an advancement in the tactics used by North Korea-linked hackers, who are no longer just exploiting bugs or using stolen credentials but are now manipulating the fundamental assumptions underlying decentralized systems. The combined impact of these incidents points to a more organized campaign than isolated hacks, as North Korea continues to escalate its efforts to siphon 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 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 transactions that never 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 checked who sent the message, not whether the message itself was correct. For security experts, this exploit highlights the issue of exploiting how the system was set up rather than a clever new hack. David Schwed, COO of blockchain security firm SVRN, emphasized, 'This attack wasn’t about breaking cryptography; it was about exploiting how the system was set up.' A key issue was a configuration choice, where Kelp relied on a single verifier to approve cross-chain messages, a setup that is faster and simpler but 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 on this recommendation, stating that LayerZero’s default setup was to have a single verifier. Schwed argued, '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 fallout has extended beyond Kelp, as its assets are used across multiple platforms, leading to a wider stress event. '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, such as lending platforms like Aave that accepted the impacted assets as collateral and are now dealing with losses. This exploit also reveals a gap between the marketing of decentralization and its actual implementation. 'A single verifier is not decentralized,' Schwed stated. 'It’s a centralized decentralized verifier.' Urbelis broadened this perspective, 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 like data providers or infrastructure, which are increasingly the focus of attackers. The recent targeting by the Lazarus group can be attributed to this shift, as they have 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 sitting underneath more visible applications, and 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 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 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.