Top 10 Ransomware Attacks Through 2026: The Most Expensive Mistakes (and the Defenses That Work)

Table of Contents

• The hairline cracks behind billion-dollar ransomware attacks
• Change Healthcare
• Cencora
• CDK Global
• Colonial Pipeline
• PowerSchool
• MGM Resorts
• Kaseya
• Jaguar Land Rover
• JBS Foods
• Yale New Haven Health
• Ransomware defense checklist and skills roadmap
• Frequently Asked Questions

Change Healthcare

In early 2024, a single missing MFA prompt on a remote access account helped trigger one of the most disruptive healthcare incidents on record. Ransomware operators tied to ALPHV/BlackCat slipped into Change Healthcare’s environment, encrypted critical systems, and exfiltrated massive amounts of data. Analysts later estimated the total damage - including direct costs, business interruption, and remediation - at over $2.45-$2.87 billion, making it the largest healthcare cyber incident in U.S. history in many 2025 cost reviews and in roundups of major attacks such as SOCRadar’s analysis of top ransomware events.

The tiny crack: a single portal account without MFA

Investigators traced the initial access back to a single Citrix portal account that did not have multi-factor authentication turned on. That was the hairline fracture in the foundation: one externally exposed login, still active, secured only by a password that could be guessed, stolen, or reused from another breach. Once authenticated, attackers were able to move laterally, escalate privileges, and eventually hit core payment and claims systems that pharmacies and hospitals relied on every day.

Why the impact was so massive

Because this one account sat in a load-bearing part of the environment, the operational fallout was brutal. Pharmacies across the U.S. struggled to verify insurance or process prescriptions. Hospitals and clinics couldn’t get claims out the door, and many small practices had to tap credit lines or emergency loans just to make payroll. On top of the reported $22 million ransom payment in Bitcoin, there were months of recovery work, regulatory scrutiny, and long-term reputational damage. It’s a textbook example of how identity failures in healthcare - already one of the most targeted sectors in recent ransomware trend reports from TechTarget - can ripple into patient care and the broader economy.

Defenses that work (and the skills behind them)

U.S. agencies like CISA and the FBI have been blunt: universal MFA and stronger identity governance would prevent a huge share of ransomware incidents, including cases very similar to this one. CISA’s own ransomware best practices emphasize that remote access points and administrative interfaces should never rely on passwords alone, and that organizations should continuously monitor for unusual login behavior, as outlined in its cybersecurity best practices guidance. For a junior defender, this incident maps directly to learnable skills in Identity and Access Management (IAM) and network defense and detection: configuring SSO and MFA, implementing least-privilege access, and spotting lateral movement and privilege escalation in logs. Those are exactly the kinds of controls you practice in ethical, lab-based environments - not against real organizations - when you work through structured training and prepare for roles on SOC or IAM teams.

Seen through that basement flashlight beam, this wasn’t an exotic nation-state zero-day; it was a missing lock on a highly visible door. Learning how to harden those doors - and how to spot similar cracks in identity and network design before attackers do - is exactly where many beginners can make a real-world impact early in their security careers.

Cencora

On paper, the Cencora case looks almost simple: a big pharmaceutical distributor gets hit, pays a massive ransom, and gets back to work. Underneath that line on the ledger is what may be the largest known single ransomware payout so far - roughly $75 million in Bitcoin, reportedly to the Dark Angels group. That figure alone pushed Cencora to the top of several “most expensive attacks” lists, including analyses of record payouts in Prolion’s review of high-cost ransomware incidents.

What actually happened

In early 2024, attackers infiltrated Cencora’s corporate IT systems, stole large volumes of data, and then deployed ransomware to maximize pressure. The pattern mirrored many modern campaigns: initial access through compromised credentials or an exposed remote service, quiet lateral movement and privilege escalation, extensive data exfiltration, and only then encryption. Unlike some victims that refuse to pay, Cencora reportedly agreed to the roughly $75 million demand - nearly double headline-making payouts like CNA Financial’s $40 million in 2021 - in hopes of speeding recovery and limiting data exposure.

The crack: flat networks and over-trusted access

The hairline fracture here wasn’t a single dramatic exploit; it was the way internal access was structured. Once attackers stepped through the first door, they were able to roam widely across corporate systems that were insufficiently segmented from sensitive data stores. Shared credentials, broad admin rights, and weak separation between everyday business systems and high-value repositories created a situation where one compromised foothold could see far more of the house than it should have. From a junior defender’s perspective, this is where skills in network architecture, least privilege, and segmentation become load-bearing, not “nice to have.”

Why the record ransom wasn’t the real finish line

Writing the check (or rather, signing the Bitcoin transaction) didn’t make the underlying risk disappear. Modern ransomware operations are increasingly about double or triple extortion: steal data, encrypt systems, and then threaten leaks or future harassment even after payment. Industry-wide analyses, such as the 2026 ransomware trends report from Varonis on evolving extortion tactics, stress that paying offers no guarantee stolen data is destroyed or won’t resurface later in new campaigns. For incident responders, that means the focus has to be on containment, forensics, and long-term hardening - not on treating the ransom as a magic reset button.

Defensive skills this maps to

Strip away the record-breaking price tag, and Cencora is really a lesson in limiting blast radius. The most relevant skills for beginners and career-switchers are the unglamorous ones: designing and enforcing network segmentation, implementing least-privilege access for both users and service accounts, and tuning monitoring to spot unusual data flows out of critical systems. In a lab or training environment, that means practicing firewall rule design, mapping data flows, and using detection tools to catch lateral movement and large exfiltration attempts - always against test environments you own or have explicit permission to use, never against real organizations. Those are the sticky notes you want on your own inspection report long before a number like “$75 million” ever appears.

CDK Global

When CDK Global went down, it was like watching the power cut out on an entire neighborhood because one contractor messed up a central junction box. This single automotive SaaS provider supports core systems for nearly 15,000 dealerships across North America, and when ransomware hit in June 2024, those dealers suddenly found themselves back on pen-and-paper. Attackers reportedly demanded about $25 million (387 Bitcoin), and while CDK has never confirmed payment, multiple incident reviews estimate cumulative dealer losses around $1 billion in lost sales and extra labor, placing the event among the top cyberattacks highlighted in resources like NovelVista’s roundup of major recent cyber incidents.

How one vendor became a single point of failure

CDK’s software runs almost everything front-of-house and back-of-house for many dealerships: sales, service, financing, inventory, even some customer communication. Once ransomware operators breached CDK’s environment, the company shut most systems down, attempted to restore, and was reportedly hit again shortly after. For weeks, dealers couldn’t easily generate contracts, check inventory, or book service appointments. Some improvised with spreadsheets and text messages; others simply lost business. Analyses of large 2024-2025 ransomware events, such as those covered in NordLayer’s overview of high-impact ransomware attacks, repeatedly point to this kind of SaaS concentration risk: one cloud provider quietly becomes the “central switch” for thousands of downstream businesses.

The crack: social engineering plus over-trusted integrations

The entry point here appears to be a mix of good old-fashioned social engineering and weaknesses in how software and environments were segmented. Public reporting suggests attackers used phishing or vishing to gain internal access, then took advantage of weak separation between development, support, and production systems. Downstream, many dealerships had granted CDK broad, persistent access into their own environments through APIs and integrations, often with more permissions than strictly necessary. For a junior defender, this is exactly where skills in phishing and vishing detection, secure integration design, and vendor access hardening come into play - not to imitate the attackers, but to recognize and close those cracks in a controlled, ethical lab setting before someone malicious finds them.

Defenses and career skills this incident highlights

On the defensive side, CDK Global reads like a checklist for supply-chain and SaaS resilience. Organizations that rely on a vendor this heavily need to do more than just price and feature comparisons: they need serious third-party risk management. That means asking pointed questions about how production is segmented from support, how backups are structured, and what the vendor’s incident response plan really looks like in practice. It also means designing integrations so that vendor accounts and APIs follow least-privilege principles and can be turned off quickly if needed, and maintaining business continuity plans that let dealers keep operating - even in a degraded mode - if their main SaaS platform suddenly disappears.

For beginners and career-switchers, this incident puts a spotlight on roles like third-party risk analyst, vendor security assessor, and security architect. The day-to-day work in those jobs looks a lot like walking through that digital “house” with a flashlight and a legal pad: mapping where vendors plug into your systems, tagging high-risk dependencies, and insisting on stronger controls before the wiring gets overloaded. Those are skills you can build step by step, starting with learning how to read SOC 2 reports, understand API permissions, and model what happens to the business if a key SaaS provider goes dark for days.

Colonial Pipeline

The Colonial Pipeline incident is still the go-to example of how a single, boring oversight can snowball into a national crisis. In May 2021, the DarkSide ransomware group hit the largest fuel pipeline in the U.S., pushing Colonial to shut down operations that normally carry around 45% of the East Coast’s fuel. The company paid a $4.4 million ransom in Bitcoin, and the FBI later clawed back about $2.3 million of that payment, as documented in investigations like Huntress’s case study on the attack. By then, fuel shortages, long gas lines, and a declared state of emergency were already front-page news.

The crack: a reused password with no MFA

Investigators traced the initial breach to a single VPN account that was still active, protected only by a password that had already appeared in a previous data breach and on dark web dumps. There was no multi-factor authentication on that remote access path. In other words, anyone who had that password could walk in from the internet as if they were a legitimate employee. This is classic credential-stuffing territory: attackers try exposed username/password combos across remote portals until something works. For defenders, the lesson is squarely in identity and access management (IAM): enforce MFA on every external entry point, monitor for use of credentials known to be compromised, and routinely disable stale accounts. In lab environments, SOC analysts practice spotting this pattern in VPN logs and identity provider alerts; in the real world, doing it ethically means working only on systems you’re responsible for, never on random corporate logins you find online.

The real cost: from one login screen to gas lines

Technically, the ransomware hit Colonial’s business IT network, not the operational technology (OT) that directly controls pumps and valves. But because the company couldn’t be sure the intrusion was contained, it shut down pipeline operations as a precaution. According to timelines compiled by U.S. homeland security researchers, including the Homeland Security Digital Library’s chronology of the Colonial attack, that decision led to temporary fuel shortages, price spikes, and panic buying along the East Coast, plus tens of millions of dollars in business interruption costs and remediation work. The ransom itself became just one line on a much longer incident report, which also included regulatory scrutiny, congressional hearings, and long-term reputational damage.

Defenses and starter skills this incident teaches

Strip away the headlines, and Colonial Pipeline is really a case study in basic-but-load-bearing controls. On the technical side, that means enforcing MFA on all VPNs and remote portals, implementing strong password hygiene and breach checks, and moving toward Zero Trust Network Access (ZTNA), where access decisions consider device posture and user behavior, not just a password. On the human side, it’s about building SOC and IAM skills: learning to read authentication logs, recognize impossible travel or odd access patterns, and respond quickly when a high-value account looks suspicious. These are exactly the kinds of skills that entry-level analysts and engineers can learn in structured training and practice in safe lab setups, so that the next time a reused password shows up on a figurative inspection report, someone knows to circle it in red and fix it before the fuel stops flowing.

PowerSchool

PowerSchool’s breach is what happens when you realize the whole wiring harness for your school district runs through a vendor’s support portal - and that portal just got popped. Between December 2024 and early 2025, attackers compromised PowerSchool systems, stole data tied to roughly 62 million students and 9.5 million teachers, and deployed ransomware. The company reportedly paid around $2.85 million to the attackers, but that was only the beginning: stolen data was allegedly reused throughout 2025 to extort individual school districts, turning one incident into a long, painful drip of follow-on threats, as noted in several 2025 breach roundups such as PKWARE’s analysis of major data breaches.

The quiet crack: shared portals and powerful remote tools

The initial access path appears to center on compromised credentials for a shared customer support portal and remote maintenance tools. In plain language: the same doors and keys used by PowerSchool staff to help districts troubleshoot issues became the attackers’ doorway into sensitive systems. Weak or reused passwords, limited multi-factor authentication coverage, and remote tools that had broad, always-on access created a situation where breaking into one account could quickly expose many. For a junior security person, this is where skills in secure SaaS administration, remote access hardening, and identity hygiene matter more than any flashy exploit research.

Why paying once didn’t solve the problem

Even after the initial ransom was reportedly paid, districts kept getting hit with new extortion demands based on the same stolen data. That’s the uncomfortable reality of today’s ransomware ecosystem: data theft and long-term extortion often matter more than the encryption itself. Sector-wide studies, including the U.S.-focused state of ransomware report from Emsisoft, highlight that education is repeatedly targeted because schools hold rich personal data but often run on thin security budgets and legacy systems. Once that data is out, there is no technical way to “un-leak” it, which means the real defense has to happen before attackers ever get in.

Defensive focus areas (and how beginners plug in)

Seen through the basement-inspection lens, PowerSchool is less about an unstoppable super-hacker and more about unglamorous cracks in how shared tools and data flows were designed. The practical fixes line up neatly with entry-level skill paths: enforcing strong authentication and MFA on support portals, using just-in-time access so remote tools are off by default, segmenting vendor access away from the most sensitive student records, and practicing data minimization so third parties only store what they truly need. In a lab or training environment, you can safely practice locking down test portals, configuring role-based access, and modeling what happens if a vendor account is compromised - always within systems you control or have explicit permission to use. Those are the sticky notes you want to see on your own “inspection report” before the slow drip of vendor risk turns into a flood of extortion emails for millions of families.

MGM Resorts

MGM Resorts’ ransomware story doesn’t start with malware; it starts with a phone call. In September 2023, attackers linked to ALPHV reportedly called MGM’s IT help desk, convincingly impersonated an employee, and talked their way into a reset of that person’s access. With valid credentials and fresh authentication factors in hand, they pivoted into MGM’s environment and disrupted core systems. For days, slot machines went dark, digital room keys stopped working, and reservation systems struggled, contributing to about $100 million in lost revenue and recovery costs. Caesars Entertainment, hit by a similar group around the same time, reportedly chose a different path and paid roughly $15 million to regain control.

The crack: a trusting help desk and voice alone

Technically, there was no elite zero-day here. The hairline fracture was a help desk workflow that trusted what it could hear. The attackers used vishing (voice phishing) to supply just enough employee details to sound legitimate, then convinced staff to reset authentication factors. Once that reset was granted, they could enroll their own devices, log in as the victim, and escalate privileges from there. For defenders, this is a classic identity problem wrapped in a social-engineering shell: even the strongest MFA is useless if an attacker can simply talk someone into resetting it for them. It’s exactly why modern ransomware trend reports, such as Infosecurity Magazine’s analysis of ransomware tactics, highlight social engineering against IT support as a growing frontline threat.

Why this matters for beginners: people, process, and logs

From a career-switcher’s perspective, MGM’s incident sits at the intersection of three learnable areas: security awareness and training, help desk process design, and SOC-style monitoring. On the human side, support staff need clear playbooks: multi-channel verification for sensitive requests, mandatory callbacks to known numbers, and hard “no” rules for certain changes without supervisor approval. On the technical side, SOC analysts need to be able to spot unusual patterns that might follow a social-engineering success, like sudden MFA resets, new device enrollments, or admin actions from unusual locations. Recent threat forecasts from organizations like KnowBe4 warn that AI will make these scams more convincing, with deepfake voices and hyper-personalized pretexts becoming common, which is why they stress that “continuous, realistic social engineering testing is becoming a must-have, not a luxury” in their cybersecurity predictions.

Defensive changes and entry-level skills

Practically, the fixes here are more about tightening screws than installing shiny new tools: stronger help desk scripts, mandatory second-factor verification for any MFA reset, closer coordination between IT support and security, and behavior-based detection tuned to identity changes. For beginners, that translates into concrete, ethical skills you can practice in lab environments and simulations: designing phishing and vishing awareness exercises, writing or following secure support procedures, and building basic detections for suspicious account activity. None of that involves tricking real employees at real companies without consent; it involves making sure that when someone tries to replay MGM’s playbook against your organization, there’s a trained human and a well-tuned alert there to stop it before the metaphorical wiring catches fire.

Kaseya

The Kaseya VSA incident is the moment you realize the service panel in your basement isn’t just powering your house - it’s secretly wired into about 1,500 other homes. In July 2021, the REvil ransomware group exploited a flaw in Kaseya’s VSA remote management software, commonly used by managed service providers (MSPs), and pushed ransomware to roughly 1,500 downstream businesses almost simultaneously. REvil demanded a $70 million payment for a universal decryptor, but Kaseya ultimately did not pay and later obtained a decryptor through a third party, as detailed in the U.S. National Counterintelligence and Security Center’s official case study of the Kaseya VSA supply chain attack.

How a management update became a ransomware delivery truck

Technically, the attackers took advantage of a zero-day authentication bypass in VSA. That flaw let them impersonate the product’s own update mechanism and deploy ransomware as if it were a legitimate software update from Kaseya. Because many MSPs centrally managed patching, monitoring, and scripting through VSA, the compromised server became a distribution hub: one malicious update, thousands of endpoints encrypted. For defenders, the important detail isn’t the specific exploit code (which you should only ever study in controlled labs, not on live systems you don’t own); it’s the implicit trust placed in remote administration tools and update channels.

The structural crack: over-trusted MSPs and remote tools

The real hairline fracture wasn’t just the zero-day; it was how much power VSA and the MSPs running it had inside customer networks. Many environments gave the tool broad, always-on access with local admin privileges across servers and workstations, minimal segmentation, and limited behavioral monitoring. That’s great for convenience and terrible for blast radius. From a junior defender’s perspective, this incident is a masterclass in why least privilege, network segmentation, and secure configuration of remote monitoring and management (RMM) tools are load-bearing responsibilities, not afterthoughts. Your job isn’t to find the next zero-day; it’s to make sure that even if one exists, it can’t turn your entire client base into a single domino line.

Defenses and starter skills this attack puts in the spotlight

Kaseya’s own post-incident updates and industry analyses, such as Fortress Information Security’s breakdown of the Kaseya ransomware attack, highlight a familiar set of mitigations. Organizations should tightly restrict what remote tools can do and where they can reach, deploy application allowlisting and robust EDR/XDR so that unusual behavior is caught even when it originates from a “trusted” tool, and run serious vendor risk assessments for MSPs before handing them keys to the kingdom. For beginners, this translates into concrete skills: learning to design segmented network zones, writing and reviewing access policies for RMM platforms, understanding how vulnerability management and Continuous Threat Exposure Management (CTEM) programs surface high-impact exposures, and tuning detections for abnormal use of admin tools. All of that can and should be practiced ethically in lab environments, treating Kaseya as a cautionary tale of what happens when convenience quietly overrides containment.

Jaguar Land Rover

Jaguar Land Rover’s ransomware incident is where the abstract idea of “data breach” slams straight into conveyor belts and assembly lines. In 2025, the automaker suffered what U.K. outlets described as “Britain’s costliest cyberattack ever”, with production lines disrupted and parts shortages rippling through its supply chain. Coverage in major ransomware roundups, including analyses of large 2024-2025 industrial attacks from sources like BlackFog’s review of high-impact ransomware incidents, consistently points to JLR as a milestone example of cyber-physical risk: a digital event that quickly turned into real-world downtime.

When cyber issues shut down physical manufacturing

Unlike a purely “IT-side” incident where email or billing systems go offline, this attack hit systems tied closely to manufacturing and logistics. Plants had to pause production, suppliers were left waiting on updated orders, and dealerships downstream saw knock-on delays in getting vehicles to customers. In modern automotive environments, planning, inventory, robotics, and even quality checks often depend on tightly integrated IT and operational technology (OT). When ransomware cuts into that nervous system, you don’t just lose access to files - you can’t move parts, start builds, or ship completed cars.

The crack: complex supply chains and OT blind spots

Public reporting suggests a familiar mix of root causes: supply chain infiltration via a trusted partner or vendor, and zero-day exploits against systems that weren’t yet patched because nobody knew they were vulnerable. Automotive manufacturing networks are often a patchwork of legacy OT gear, newer cloud-connected services, and third-party maintenance links. That complexity makes it hard to see where all the “wires” really run, and even harder to segment cleanly. The result is a subtle but dangerous crack: a vendor VPN or remote-maintenance account that quietly has more reach into factory systems than anyone realized. For beginners, this is where skills in network segmentation, asset inventory, and OT-aware access control become load-bearing, not optional.

What this teaches about future threats and needed skills

Security forecasts have been warning that ransomware is moving deeper into critical infrastructure and manufacturing, with attackers increasingly targeting environments where downtime hurts most. Analysts at firms like Rapid7 note that defenders must start treating identity, behavior, and cyber-physical impact as core detection signals, not afterthoughts, especially as threats evolve in industrial and IoT-heavy settings, a theme they highlight in their forward-looking cybersecurity predictions for complex environments. For career-switchers, Jaguar Land Rover’s experience points directly at growing niches: ICS/OT security (understanding PLCs, SCADA, and plant networks), vendor risk and contract security requirements, and risk management that translates technical issues into real business impact (“What happens if this line is down for a week?”).

All of that is work you can learn and practice ethically in controlled labs and simulations: mapping “as-built” network diagrams for test factories, experimenting with segmentation strategies that keep OT separate from corporate IT, and reviewing hypothetical vendor access requests with a skeptic’s eye. The lesson from JLR isn’t that automotive plants are uniquely doomed; it’s that once your digital and physical systems are tightly coupled, a quiet configuration lapse or over-trusted supplier link can be the small crack that takes real-world production off the road.

JBS Foods

JBS Foods shows how a “data breach” can turn into cows standing idle and supermarket shelves getting more expensive. In May 2021, ransomware group REvil hit one of the world’s largest meat processors, forcing JBS to shut down plants in the U.S. and Australia and temporarily affecting about 20% of the U.S. meat supply. The company later confirmed paying an $11 million ransom in Bitcoin to regain control, a figure widely cited in incident analyses such as Claroty’s deep dive into the JBS attack.

The crack: legacy systems and “unusually poor” security

The hairline fracture at JBS wasn’t a single exotic exploit; it was years of underinvestment in basic cybersecurity. Internal Department of Homeland Security records later obtained by journalists painted a blunt picture of the company’s posture before the attack: flat networks, legacy systems, and weak access controls created an environment where a foothold in IT could plausibly threaten operations. As one investigation summarized it in plain language:

“JBS’s cybersecurity was ‘unusually poor’ prior to the 2021 ransomware attack, according to internal Homeland Security documents.” - Investigate Midwest, reporting on DHS assessments

For a junior defender, that phrase is a red circle on the inspection report. It points straight at foundational skills: asset inventory, patch management, basic network segmentation, and identity hygiene. None of that involves hunting for zero-days; it’s the unglamorous work of figuring out what you actually have, how it’s connected, and where passwords and privileges have quietly sprawled over time.

From encrypted servers to meat supply disruption

Technically, the ransomware hit JBS’s IT systems, but the company chose to halt operations in several plants rather than risk the infection spreading into operational technology (OT) that controls processing lines. That precautionary shutdown translated into immediate production slowdowns and concerns about short-term shortages and pricing. Claroty’s analysis of the incident frames it as a wake-up call for the entire food and beverage sector, arguing that the JBS attack “puts food and beverage cybersecurity to the test” by showing how quickly a single compromise can echo through a global supply chain when IT and OT are tightly coupled, as detailed in their post-incident case study. Once again, the ransom payment was just one line item; the bigger bill came from downtime, recovery, and accelerated security upgrades.

Defenses and starter skills this incident highlights

Seen through the basement metaphor, JBS is a house with old wiring, no circuit breakers, and a haphazard addition bolted on the back. The defensive priorities are straightforward but not easy: modernize and segment legacy IT and OT networks, run regular third-party assessments before attackers do, and rehearse cross-functional incident response so plant engineers, IT, and security know how to work together under pressure. For beginners and career-switchers, this maps to several concrete, ethical skill paths: learning the basics of ICS/OT security, practicing network segmentation in lab environments, getting comfortable with frameworks like NIST CSF, and participating in tabletop exercises that simulate what happens when a core business system goes offline. The goal is not to break into real food plants; it’s to be the person who knows where the cracks are and how to reinforce them before the next ransomware crew comes knocking.

Yale New Haven Health

Yale New Haven Health’s ransomware incident is what it looks like when the worst mold in your house doesn’t start in your living room, but in a contractor’s crawlspace you rarely think about. In March 2025, attackers compromised a third-party vendor that processed data for the health system and used that foothold to access sensitive records. Roughly 5.6 million patient records were exposed, and by late 2025 Yale New Haven Health agreed to an $18 million class-action settlement; analysts estimated that the broader ecosystem of remediation, regulatory work, and security upgrades pushed total impact toward $500 million, as summarized in healthcare breach overviews like HIPAA Journal’s report on the largest breaches of 2025.

When your vendor’s crawlspace floods

On paper, the health system didn’t “lose” the data itself; the compromise happened inside a vendor’s environment that handled analytics and processing on its behalf. But from a patient’s point of view, that distinction doesn’t matter: their protected health information still ended up in criminal hands. Recent industry research, including the healthcare-focused sections of Cybersecurity Ventures’ 2025 Cybersecurity Almanac, has been warning that third-party breaches like this are a primary driver of rising breach counts and costs in the sector. Hospitals and clinics are under pressure to outsource billing, analytics, and specialty services, which means more copies of the same sensitive data living outside the walls of any one organization’s direct control.

The crack: data and controls that live offsite

The hairline fracture here wasn’t some exotic, one-in-a-million attack; it was the combination of large volumes of mirrored patient data and weaker security at a downstream vendor. Inadequate patching, limited access controls, and insufficient monitoring in that vendor’s environment gave attackers the room they needed to deploy ransomware and exfiltrate data. For defenders, this lands squarely in the world of governance, risk, and compliance (GRC) and third-party risk management: understanding exactly which vendors hold which categories of data, what security promises they’ve made in contracts, and how you verify that those promises are actually being kept. From a junior practitioner’s perspective, that means learning to read SOC 2 reports, map data flows, and ask uncomfortable-but-necessary questions about how a partner segments, encrypts, and audits the information you send them.

Defensive lessons and beginner-friendly roles

Viewed through that basement-inspection lens, Yale New Haven Health’s experience underlines that you can’t just “trust but verify” with vendors; you have to architect your reliance on them. Stronger practices include keeping an up-to-date inventory of all third parties that touch patient data, classifying them by criticality, baking concrete security requirements (MFA, encryption, logging, patching SLAs, and breach notification timelines) into contracts, and moving from annual questionnaires to more continuous monitoring of vendor posture. In heavily regulated environments like healthcare, that work doesn’t happen in the shadows; it often lives in visible roles such as vendor risk analyst, privacy analyst, or GRC specialist, which are popular entry points for career-switchers who may not have a deep technical background but are comfortable with policy, documentation, and stakeholder communication.

Ethically, all of this is about defense, not exploitation. When you practice these skills in a lab or training setting, you’re learning how to spot missing controls in hypothetical vendor setups, not poking at real hospital partners without permission. The goal is to be the person who knows where the third-party cracks are and can get them circled on the organizational “inspection report” before attackers trace that same line across a vendor’s wall and turn a quiet oversight into a half-billion-dollar problem.

Ransomware defense checklist and skills roadmap

By the time you get to the end of this “inspection report,” the rankings matter a lot less than the pattern. Whether the ransom was eight figures or the downtime knocked out one factory or thousands of schools, the same kinds of quiet flaws keep showing up: weak identity checks, flat networks, untested backups, and over-trusted vendors. Modern guidance on ransomware, like the UK’s practical advice on mitigating malware and ransomware attacks from the NCSC, keeps coming back to the same message: focus on fundamentals, not just on the latest headline strain.

Lock the doors: identity and human factors

A huge share of the attacks in this list began with the simplest cracks: a password reused from another breach, a VPN or portal without MFA, or a help desk that could be talked into resetting someone’s account. That’s the realm of identity & access management and phishing and vishing resilience. A practical checklist here includes enforcing MFA on all remote and administrative access, monitoring for logins using known-compromised credentials, hardening help-desk procedures for MFA resets, and running regular, realistic social-engineering simulations. For beginners, these are accessible skills: learning how SSO and MFA actually work, reading authentication logs, and designing or delivering awareness training that helps colleagues spot suspicious emails and calls.

Contain the blast: networks, endpoints, and recovery

Once an attacker gets a foothold, the next question is how far they can roam and how quickly you can bounce back. This is where network segmentation, strong endpoint protection, and immutable backups become load-bearing controls. Ransomware-focused playbooks, like those highlighted in real-world response guides such as TenHats’ walkthrough on responding to ransomware incidents, stress having at least one backup that malware can’t encrypt, testing restores regularly, and using EDR/XDR tools to spot lateral movement and early-stage ransomware behavior. For entry-level defenders, that often looks like learning firewall basics, practicing building simple segmented lab networks, getting comfortable with EDR alerts, and helping run backup restore tests so you know they work before you ever need them.

Tame your vendor sprawl and exposures

Many of the biggest incidents in this list didn’t start “inside” the victim at all; they started in a vendor’s environment or a shared SaaS platform. That’s the crawlspace where a lot of modern risk hides, and it calls for governance, risk & compliance (GRC) skills as much as technical ones. A practical checklist means keeping an inventory of every vendor that touches sensitive data, classifying them by criticality, baking minimum security requirements into contracts (MFA, logging, patching SLAs, breach notification), and moving toward continuous exposure management rather than one-off questionnaires. For newcomers, that might translate into roles like vendor risk analyst or junior GRC specialist, where you learn to map data flows, review audit reports, and turn vague “we take security seriously” claims into concrete, testable controls.

Skills roadmap: turning the checklist into job titles

If you imagine your future security career as the person with the flashlight and the legal pad, this checklist becomes a roadmap. Start with one or two areas, build hands-on experience in labs and training programs, and aim for entry-level roles that let you practice spotting and fixing these cracks for real organizations (legally, with permission). Over time, you’ll move from checking individual outlets - one VPN, one backup, one vendor contract - to shaping how the whole “house” is wired.

Frequently Asked Questions