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

Barely three weeks after hackers linked to North Korea employed social engineering to breach the cryptocurrency trading firm Drift, another significant exploit has been attributed to the nation, this time targeting Kelp, a restaking protocol integrated into LayerZero's cross-chain infrastructure. This recent attack suggests an advancement in the strategies employed by North Korea-linked hackers, who are now not only seeking vulnerabilities or stolen credentials but also exploiting fundamental assumptions underlying decentralized systems. The combined impact of these incidents points to a more structured approach than isolated hacks, as North Korea intensifies 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 drained across 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 thereby approving 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 exploit highlights a simpler issue - the system checked the sender's identity, not the message's accuracy. For security experts, this is less about a novel hack and more about exploiting the system's setup. 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 the configuration choice, with Kelp relying on a single verifier to approve cross-chain messages, a decision made for speed and simplicity but one that removes a critical safety layer. Following the incident, LayerZero has recommended using multiple independent verifiers to approve transactions, akin to requiring multiple signatures on a bank transfer. However, some have pushed back against 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 aftermath has not been limited to Kelp, as its assets are used across multiple platforms, leading to a wider impact when one link breaks. Lending platforms like Aave, which accepted the impacted assets as collateral, are now dealing with losses, turning a single exploit into a broader stress event. The attack also reveals a discrepancy 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 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.' This means that 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 targeting of cross-chain and restaking infrastructure by Lazarus, as noted by Urbelis, highlights this shift. 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 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 demonstrated how exposed the ecosystem remains to familiar vulnerabilities, 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.