North Korea's Crypto Attack Strategy Expands, Targets DeFi

Less than three weeks after hackers linked to North Korea used social engineering to breach crypto trading firm Drift, another major exploit has been carried out on Kelp, a restaking protocol connected to LayerZero's cross-chain infrastructure. This attack signifies an evolution in the tactics of North Korea-linked hackers, who are now exploiting fundamental assumptions in decentralized systems, rather than just seeking out vulnerabilities or stolen credentials. The incidents collectively suggest a more organized effort by North Korea to intercept 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 across the Drift and Kelp 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 non-existent transactions. 'The security failure is simple: a signed lie is still a lie,' Urbelis said. 'Signatures guarantee authorship; they do not guarantee truth.' This exploit highlights the issue of configuration choices, with Kelp relying on a single verifier to approve cross-chain messages, a setup that is faster and simpler but removes a critical safety layer. LayerZero has since recommended using multiple independent verifiers, similar to requiring multiple signatures on a bank transfer. However, some have pushed back on this, stating that LayerZero's default setup was to have a single verifier. The fallout from the exploit has extended beyond Kelp, affecting lending platforms like Aave that accepted impacted assets as collateral, turning a single exploit into a wider stress event. The attack 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.' Urbelis added, '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.' The shift in targeting by attackers, particularly Lazarus, towards cross-chain and restaking infrastructure, underscores the vulnerability of these critical but complex layers that move assets between systems or allow them to be reused. These layers hold large amounts of value, making them attractive targets, and their misconfiguration can lead to significant exploits. As attackers adapt, the biggest risk may not be unknown vulnerabilities but known ones that are not fully addressed, highlighting the need for security to be treated as a requirement rather than a recommendation.