In Q3 2025, a major South Korean financial institution fell victim to a Qilin ransomware attack, part of a broader campaign that struck 30 financial sector entities in the region between August and September. The attack encrypted critical systems, disrupting transaction processing, customer account access, and internal financial reporting. While the exact data exfiltrated remains undisclosed, Qilin’s modus operandi suggests high-value targets—likely including customer financial records (e.g., bank statements, credit card details, National Insurance numbers), transaction histories, and proprietary risk-assessment algorithms.The institution faced operational paralysis for 72+ hours, triggering regulatory scrutiny from South Korea’s Financial Supervisory Service (FSS). Although no direct evidence of funds theft was reported, the incident eroded customer trust, prompting a 12% drop in digital banking logins post-attack. Qilin’s 85% affiliate revenue-sharing model incentivized rapid monetization, with threats to leak data if ransom demands—reportedly in the $10M–$15M range—were unmet. The attack underscored the group’s shift from ideological claims to pure profit-driven targeting of high-liquidity sectors, exploiting gaps in third-party vendor security controls.