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 crypto trading firm Drift, another major exploit has been carried out, this time targeting Kelp, a restaking protocol connected to LayerZero's cross-chain infrastructure. This suggests an evolution in the tactics used by North Korea-linked hackers, who are now exploiting the fundamental assumptions built into decentralized systems, rather than just looking for bugs or stolen credentials. The two incidents, which together resulted in the siphoning of over $500 million in just over two weeks, point to 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.' The Kelp exploit did not involve breaking encryption or cracking keys but rather manipulated the data feeding into the system, forcing it to rely on compromised inputs and approving transactions that never 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 the issue of a system checking who sent a message rather than whether the message itself was correct. 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 the configuration choice of Kelp relying on a single verifier to approve cross-chain messages, which, although faster and simpler to set up, removes a critical safety layer. Following the exploit, LayerZero recommended using multiple independent verifiers to approve transactions, akin to requiring multiple signatures on a bank transfer. However, some have pushed back on this recommendation, noting 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 fallout from the Kelp exploit has extended beyond the platform itself, 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. As Schwed pointed out, 'A single verifier is not decentralized. It’s a centralized decentralized verifier.' Urbelis further clarified, '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 systems appearing to be decentralized can have weak points, particularly in less visible layers like data providers or infrastructure, which are increasingly the focus of attackers. The shift in targeting by groups like Lazarus towards cross-chain and restaking infrastructure, which are critical but complex and often hold large amounts of value, may explain recent trends. These layers, being harder to monitor and easier to misconfigure, represent a significant risk, especially as attackers adapt and the gap between known vulnerabilities and their full addressing becomes both easier to exploit and more expensive to ignore.