How Did One MSP Breach Cripple 28 Korean Firms?

Today we’re speaking with an IT professional whose work at the intersection of artificial intelligence, machine learning, and blockchain gives him a unique perspective on today’s most complex cyber threats. We’ll be dissecting a recent, sophisticated supply chain attack that crippled South Korea’s financial sector, an operation dubbed “Korean Leaks.” Our discussion will explore how the Qilin ransomware group managed to compromise dozens of victims through a single managed service provider (MSP), the troubling potential collaboration between these cybercriminals and North Korean state actors, and the evolving psychological tactics used to pressure victims into paying. We’ll also examine the explosive growth of the Ransomware-as-a-Service model and what organizations can do to defend against these pervasive supply chain vulnerabilities.

The “Korean Leaks” campaign began with the compromise of a single managed service provider, GJTec, which then led to the rapid infection of numerous downstream clients. Could you walk us through how threat actors typically turn one MSP breach into such a widespread and devastating ransomware event?

It’s a classic and terrifyingly effective playbook that we see more and more. When attackers breach an MSP, they haven’t just broken into one house; they’ve stolen the master key to an entire neighborhood. The MSP has trusted, often privileged, access to the networks of all its clients for legitimate maintenance and support. Attackers exploit this pre-existing trust. They use the MSP’s own tools and credentials to move laterally into client environments, deploying their ransomware almost simultaneously across dozens of victims. This strategy provides incredible speed and scale, turning a single intrusion into a multi-victim catastrophe like the “Korean Leaks” before anyone even realizes the primary breach has occurred. It’s a method that RaaS groups seeking clustered victims find both practical and devastatingly efficient.

We’re seeing a potential connection between the financially motivated Qilin RaaS group, which has Russian origins, and a North Korean state-sponsored actor known as Moonstone Sleet. From your perspective, how do these partnerships between criminal and state actors typically function, and what are the strategic benefits for each side?

The line between cybercrime and statecraft is becoming increasingly blurred, and this potential collaboration is a prime example. These partnerships are a marriage of convenience and capability. The state-sponsored group, like Moonstone Sleet, brings sophisticated intrusion techniques and strategic objectives, in this case targeting South Korean businesses which aligns perfectly with their national interests. In return, the RaaS group, Qilin, provides a powerful, ready-made ransomware platform and a degree of plausible deniability. The state actor can conduct disruptive attacks while hiding behind a criminal facade, and the RaaS group gains access to high-value targets they might not find on their own, all while taking a cut—Qilin affiliates keep up to 80% of the ransom. It’s a symbiotic relationship where state espionage goals are laundered through a criminal enterprise for financial gain.

The Qilin affiliate’s messaging during this campaign was fascinatingly dynamic, starting with political propaganda about exposing corruption and later shifting to more direct financial extortion. What does this evolution in pressure tactics reveal about the attackers’ strategy and negotiation process?

This tactical shift tells us that the attackers are adaptable and psychologically savvy. They began the “Korean Leaks” campaign by framing it as a noble act of public service, threatening to release files that were “evidence of stock market manipulation.” This wasn’t just about data; it was about creating a public relations nightmare and pressuring victims with shame and regulatory fear. As the campaign progressed through its three waves, the narrative escalated to threatening a full-blown national financial crisis. The final shift to Qilin’s more typical, direct extortion language suggests a multi-stage negotiation strategy. It’s likely the affiliate, with guidance from Qilin’s core team—who boast of an “in-house team of journalists”—was testing different levers to see what would compel payment, moving from political posturing to raw financial threats when the initial approach didn’t yield the desired results.

The report highlights Qilin’s “explosive growth,” attributing an astonishing 29% of all ransomware attacks to the group and noting the massive spike in South Korean victims from two per month to 25. From a technical and operational standpoint, how does a RaaS operation achieve this level of market dominance so quickly?

That kind of explosive growth is the direct result of the Ransomware-as-a-Service model. Qilin doesn’t have to carry out every attack themselves. Instead, they operate like a dark-web software company, developing and maintaining the ransomware and the leak site infrastructure. They then recruit a diverse army of affiliates to do the dirty work of hacking into networks. This affiliate model allows them to scale their operations exponentially. For every successful attack, they simply take a 20% commission. For defenders, this creates an immense challenge. You’re not fighting a single, monolithic entity with predictable patterns. You’re up against countless independent actors, all armed with the same highly effective ransomware, making it incredibly difficult to track, attribute, and build effective defenses against their varied intrusion methods.

The compromise of MSPs is described as a “critical blind spot” for many organizations. Moving beyond standard advice like implementing MFA, what are some more advanced, tangible steps a company can take to vet its vendors and truly apply the Principle of Least Privilege to mitigate these supply chain risks?

This is where security needs to move from a checklist to a mindset. Vetting an MSP must go beyond their sales pitch and into a deep audit of their security posture. But the most critical internal step is a rigorous application of the Principle of Least Privilege. This means you don’t just grant your MSP admin rights to everything. You must meticulously define and enforce access controls, ensuring they can only touch the specific systems and data absolutely necessary for their job. This requires network segmentation to wall off your most critical assets. Imagine if GJTec had been restricted from accessing the core financial data of its 28 clients. A breach might still have occurred, but the blast radius would have been a small scorch mark instead of a raging inferno that resulted in the theft of over 2 terabytes of data. It’s about assuming your partners will be breached and building a resilient architecture that can withstand that event.

What is your forecast for the convergence of Ransomware-as-a-Service operations and state-sponsored threat actors?

I forecast that this convergence will not only continue but will become more formalized and sophisticated. The “Korean Leaks” campaign serves as a powerful proof of concept. State actors see the value in leveraging the operational agility, infrastructure, and plausible deniability of established RaaS platforms. RaaS operators, in turn, benefit from the advanced capabilities and strategic target selection provided by state-sponsored hackers. We’re going to see more hybrid attacks where geopolitical motives are cloaked in the guise of financial extortion. This will make attribution exponentially harder for defenders and law enforcement, and it will raise the stakes for victims, who may find themselves caught in the crossfire of international conflicts without even realizing it.

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