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 major exploit has been carried out, this time targeting 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 exploits, which resulted in the theft of over $500 million in just over two weeks, 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 is a cadence. You cannot patch your way out of a procurement schedule.' The Kelp breach did not involve breaking encryption but rather manipulating the data feeding into the system, forcing it to rely on compromised inputs and approve non-existent transactions. This exploit highlights a simple security failure: a signed lie is still a lie, as signatures guarantee authorship but not truth. The system checked who sent the message, not whether the message itself was correct, making this exploit more about manipulating the system's setup than about a new hack. A key issue was 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 have pushed back on this, noting that LayerZero's default setup was to have a single verifier. David Schwed, COO of blockchain security firm SVRN, 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 impact of the exploit has not been limited 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. This incident also exposes a gap between the marketing of decentralization and its actual implementation. As Schwed noted, 'A single verifier is not decentralized; it's a centralized decentralized verifier.' Urbelis broadly stated, '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, 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 recent targeting by Lazarus, a group linked to North Korea, of cross-chain and restaking infrastructure, underscores this shift. These layers are critical, complex, and often hold large amounts of value, making them attractive targets. 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 but 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.