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 cryptocurrency 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 that North Korea-linked hackers are adapting their methods, moving beyond exploiting bugs or stolen credentials to manipulating the fundamental assumptions underlying decentralized systems. The combined incidents of Drift and Kelp point to a more organized effort by North Korea 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's a cadence. You cannot patch your way out of a procurement schedule.' More than $500 million was stolen across these two exploits in just over two weeks. The Kelp breach did not involve breaking encryption but rather manipulating the data fed into the system, forcing it to rely on compromised inputs and approve transactions that did not occur. 'The security failure is simple: a signed lie is still a lie,' Urbelis noted. 'Signatures guarantee authorship; they do not guarantee truth.' This exploit highlights the issue of 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 argue that LayerZero's default setup was to have a single verifier, and the onus should not be on users to configure the system securely. The fallout from the Kelp exploit has not been contained, affecting lending platforms like Aave that accepted the impacted assets as collateral, turning a single exploit into a broader stress event. This incident also reveals a gap between the marketing of decentralization and its actual implementation. 'A single verifier is not decentralized,' said David Schwed, COO of blockchain security firm SVRN. 'It's a centralized decentralized verifier.' The attack exposes weaknesses in the less visible layers of the cryptocurrency ecosystem, such as data providers or infrastructure, which are becoming the focus of attackers. As North Korea-linked hackers continue to adapt, targeting cross-chain and restaking infrastructure, the biggest risk may not be unknown vulnerabilities but known ones that are not fully addressed. The Kelp exploit demonstrates how exposed the ecosystem remains to familiar weaknesses, especially when security is treated as a recommendation rather than a requirement.