South Korea Financial Sector Hit by Qilin Ransomware Linked to Russian, North Korean Actors

• Qilin ransomware surged in South Korea, with 25 incidents in September 2024, far exceeding the average of two monthly cases.

• The attacks focused on the financial sector, compromising 24 entities and marking South Korea as the second-most affected country globally by ransomware this year.

• Bitdefender’s analysis revealed over 1 million files stolen in three waves, including potential military and economic intelligence valued at billions.

Discover the Qilin ransomware attack details in South Korea: Russian-North Korean hackers stole 2TB from banks. Learn impacts and defenses in this crypto finance security breakdown. Stay informed—protect your assets now.

What is the Qilin Ransomware Attack in South Korea?

The Qilin ransomware attack in South Korea represents a sophisticated cyber operation blending Ransomware-as-a-Service tactics with state-sponsored elements, primarily targeting the nation’s financial infrastructure. Cybersecurity firm Bitdefender detailed in its October 2024 Threat Debrief how attackers compromised managed service providers to deploy malware across 33 incidents this year, with 25 linked to Qilin. This surge, especially 25 attacks in September alone, highlights vulnerabilities in supply chains that exposed sensitive banking data to extortion.

How Did Russian and North Korean Hackers Target South Korean Financial Institutions?

The operation leveraged initial access through managed service provider (MSP) compromises, a tactic that allowed rapid lateral movement into financial networks. Bitdefender’s investigation, initiated after detecting the anomaly in September 2024 ransomware reports, confirmed involvement from Qilin, a Russian-rooted group operating under a RaaS model, alongside potential North Korean actors known as Moonstone Sleet. Of the 33 cases identified, 24 affected financial entities, resulting in the exfiltration of over 2TB of data, including documents with military and economic significance.

According to Bitdefender’s report released on October 28, 2024, South Korea ranked second globally for ransomware impacts in 2025, trailing only the United States. The attackers framed their incursions as anti-corruption efforts, using propaganda-style messages to justify data leaks. For instance, in an August 20, 2024, breach of a construction firm, hackers claimed stolen blueprints for bridges and LNG tanks held “military intelligence value,” even referencing preparation of a report for North Korean leadership in leaked forum discussions.

Victims of ransomware in Korea. Source: Bitdefender

Qilin, active throughout 2025 with over 180 claimed victims in October alone, accounts for 29% of global ransomware incidents per NCC Group’s threat intelligence. The group’s Russian origins are evident in its operations: founding member “BianLian” engages on Russian-language cyber forums, and Qilin adheres to a policy of not targeting Commonwealth of Independent States entities. Affiliates receive technical support, including an in-house team for crafting extortion materials, while core operators claim a profit share.

The Korean Leaks campaign unfolded in three phases, amassing 1 million files from 28 victims. The initial wave on September 14, 2024, exposed 10 financial management firms. Subsequent releases from September 17-19 and September 28-October 4 added 18 more, with threats to disrupt the stock market through data dumps on alleged corruption, stock manipulation, and ties to politicians. Four additional posts were removed from the leak site, possibly due to paid ransoms. Korean outlet JoongAng Daily noted on September 23, 2024, that over 20 asset managers suffered via a breach at service provider GJTec.

Bitdefender emphasized the hybrid nature of the threat: Qilin’s RaaS infrastructure combined with state actors’ espionage motives. “This operation underscores the evolving risks to critical sectors like finance, where cybercrime intersects with geopolitical tensions,” stated a Bitdefender spokesperson in the report. The firm’s expertise in endpoint security helped trace the attack vectors, revealing tactics such as posing as activists to mask data theft with political rhetoric.

Frequently Asked Questions

What Makes the Qilin Ransomware Group a Major Threat to Crypto and Financial Sectors?

The Qilin group stands out due to its RaaS efficiency, high-volume attacks, and avoidance of certain regions, per Bitdefender and NCC Group analyses. In 2025, it targeted financial hubs like South Korea’s banks, stealing sensitive data that could impact crypto exchanges and fintech via supply chain weaknesses. Victims face extortion demands averaging millions, with non-payment leading to leaks that erode market trust.

How Can Financial Institutions in South Korea Prevent Future Qilin-Style Ransomware Attacks?

To safeguard against Qilin ransomware, institutions should prioritize MSP vetting, multi-factor authentication, and regular penetration testing, as recommended by cybersecurity experts at Bitdefender. Implementing zero-trust architectures and employee training on phishing reduces initial access risks. In South Korea’s case, segmenting networks could have limited the 2TB data breach, ensuring quicker incident response and minimal financial disruption.

Key Takeaways

• South Korea’s Ransomware Surge: September 2024 saw 25 Qilin attacks, a 12-fold increase from the yearly average, focusing on finance.
• State-Sponsored Elements: North Korean Moonstone Sleet ties suggest espionage beyond extortion, with 2TB stolen data including military insights.
• Defensive Actions: Enhance supply chain security and monitor for RaaS indicators to protect crypto-adjacent financial assets from global threats.

Conclusion

The Qilin ransomware attack in South Korea exemplifies the growing nexus of cybercrime and state actors targeting financial infrastructures, as detailed by Bitdefender’s 2024 Threat Debrief. With 33 incidents in 2025 exposing vulnerabilities in banking and asset management, the operation’s 2TB data theft poses ongoing risks to economic stability and crypto ecosystems reliant on secure finance. Stakeholders must invest in robust defenses now to mitigate future threats and maintain trust in digital markets.