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

Barely three weeks after hackers linked to North Korea used social engineering to breach the crypto trading firm Drift, another major exploit has been attributed to the nation, 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 Korea-linked hackers, as they now exploit fundamental assumptions built into decentralized systems, rather than merely seeking out bugs or stolen credentials. The cumulative effect of these incidents suggests a more organized effort by North Korea to hijack funds from the crypto 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; rather, attackers manipulated the data feeding into the system, forcing it to rely on compromised inputs and approve transactions that never actually occurred. 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 that the system checked who sent the message, not whether the message itself was correct, making it less about a new hack and more about exploiting the system's setup. 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 a configuration choice, with Kelp relying on a single verifier to approve cross-chain messages, a decision that, while faster and simpler to set up, 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 have pushed back on this, 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 aftermath of the exploit has not been contained to Kelp, as its assets are used across multiple platforms, leading to a wider stress event. Lending platforms like Aave, which accepted the impacted assets as collateral, are now dealing with losses. The attack also reveals a gap between the marketing of decentralization and its actual implementation. Schwed pointed out, 'A single verifier is not decentralized; 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 Lazarus group 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, often under more visible applications, and 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 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.