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 significant exploit has been carried out, this time targeting Kelp, a restaking protocol connected to LayerZero's cross-chain infrastructure. This attack suggests an advancement in the tactics employed by North Korea-linked hackers, who are now exploiting fundamental assumptions built into decentralized systems, rather than just seeking out vulnerabilities or stolen credentials. The combination of these two incidents points to a more organized effort by North Korea to hijack 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 isolated incidents, but rather a cadence. You cannot solve these issues simply by patching them, as they are part of a larger 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; instead, attackers manipulated the data feeding into the system, forcing it to rely on compromised inputs and approve transactions that did not actually occur. As Urbelis explained, 'The security failure is straightforward: a signed lie is still a lie. Signatures guarantee the author, not the truth.' In simpler terms, the system verified who sent the message but not whether the message itself was accurate. For security experts, this exploit is less about a sophisticated new hack and more about taking advantage of how the system was configured. David Schwed, COO of blockchain security firm SVRN, noted, 'This attack wasn't about breaking cryptography; it was about exploiting the system's setup.' A key issue was the configuration choice to rely on a single verifier to approve cross-chain messages, which, while 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 in the ecosystem have pushed back against this, stating that LayerZero's default setup was to use a single verifier. Schwed emphasized, 'If you've identified a configuration as unsafe, don't offer it as an option. Security that relies on everyone reading the documentation and getting it right is not realistic.' The impact has not been limited to Kelp, as its assets are used across multiple platforms, leading to a wider stress event when one link in the chain breaks. Lending platforms like Aave, which accepted the impacted assets as collateral, are now dealing with losses. This incident also highlights the 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 expanded on this, saying, 'Decentralization is not a property a system has; it's a series of choices. And the stack is only as strong as its most centralized layer.' In practice, this means that even systems that appear decentralized can have weak points, especially in less visible layers like data providers or infrastructure, which are increasingly the focus of attackers. The shift towards targeting cross-chain and restaking infrastructure, such as what Lazarus has been doing, may explain the recent targeting. These layers are critical but complex, often underlying more visible applications, and they 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 towards what could be called the industry's plumbing - 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.