Over the past three years, cyberattacks have hit every corner of the global economy. These incidents aren’t isolated, and they reflect recurring weaknesses and overlooked entry points. For organizations focused on long-term security and operational continuity, recognizing the common patterns behind these breaches is essential.

As a penetration testing firm, we’ve analyzed some of the most high-profile cybersecurity incidents between 2023 and 2025 to distill lessons that can help businesses better prepare, detect, and defend against modern threats.

In May 2023, a zero-day vulnerability in MOVEit, a widely used file transfer solution, enabled the Cl0p ransomware group to compromise over 2,700 organizations worldwide. This breach exposed personal data of over 93 million individuals, including sensitive government, healthcare, and financial records.

Strategic Insight:
The MOVEit attack exposed the critical danger of relying on third-party software without a robust patch management strategy. Regular vulnerability assessments, combined with proactive penetration testing, are key to identifying how attackers could chain together seemingly secluded flaws.

In October 2023, the ransomware group Rhysida infiltrated the British Library, demanding millions of dollars in Bitcoin after leaking 600 GB of internal data. Recovery took months, with costs exceeding £7 million, and digital services were severely disrupted through early 2024.

Strategic Insight:
Public and nonprofit organizations are often under-resourced in cybersecurity. This attack underscores the need for Zero Trust architecture, enforced multi-factor authentication (MFA), and routine penetration testing, even in sectors that don’t consider themselves high-risk.

In December 2023, Ukrainian telecom giant Kyivstar was hit by a nation-state attack attributed to the Russian APT group Sandworm. The result: massive service outages affecting 24 million users, including air-raid alert systems, at a recovery cost of $90 million.

Strategic Insight:
This incident exemplifies how geopolitical conflict is increasingly fought in cyberspace. For businesses operating in critical infrastructure or adjacent supply chains, continuous security testing and network segmentation are non-negotiable.

In mid-2024, attackers exploited weak security practices across multiple Snowflake client environments, breaching accounts at AT&T, Ticketmaster, and Santander, among others. Over 160 customer instances were compromised, and sensitive data, ranging from PII to authentication tokens, was exposed.

Strategic Insight:
Even secure cloud platforms are only as strong as their configurations. This breach is a textbook case for implementing strong IAM policies, enforcing MFA, and conducting cloud-specific penetration tests to uncover misconfigurations before attackers do.

In February 2024, the ALPHV/BlackCat ransomware group infiltrated Change Healthcare (a UnitedHealth subsidiary), compromising the data of over 100 million patients. The breach was enabled through a Citrix portal lacking MFA, leading to data theft, business disruption, and a ransom payment reportedly over $22 million.

Strategic Insight:
Healthcare remains one of the most targeted industries due to its sensitive data and outdated systems. This incident reveals how third-party risk assessments, red teaming, and attack surface monitoring are critical components of a modern defense strategy.

In October 2024, Cloudflare mitigated a record-breaking 5.6 Tbps DDoS attack targeting a major ISP in East Asia. The attack, lasting only 80 seconds, was launched by over 13,000 compromised IoT devices.

Strategic Insight:
The scalability of DDoS attacks is growing rapidly thanks to IoT device proliferation. Even short-lived attacks can disrupt business operations, highlighting the need for robust network defenses, DDoS protection, and infrastructure resilience testing.

Cyberattacks in 2025 have pushed new boundaries, not just in how much data is stolen or how much damage is done, but in who is being targeted and why. Threat actors are aiming higher, hitting faster, and leaving longer-lasting impact.

Below are some of the year’s most significant breaches and the lessons they carry for anyone responsible for protecting digital assets.

Bybit Cryptocurrency Hack
In February 2025, the North Korean group Lazarus stole $1.5 billion in Ethereum from crypto exchange Bybit. It remains one of the largest crypto thefts in history.

Implication: Cryptocurrency platforms must adopt cold wallet segregation, hardware-level encryption, and incident response simulations.

Lee Enterprises Ransomware
Ransomware group Qilin took down operations across 75 regional U.S. newspapers, exfiltrating 350 GB of sensitive editorial and employee data.

Implication: Media companies, often overlooked in cyber strategy, require better endpoint detection, business continuity planning, and ransomware preparedness.

Yale New Haven Health Breach
In March 2025, 5.5 million patient records were exposed, including SSNs and protected health information. A third-party vendor was implicated.

Implication: As in previous healthcare breaches, third-party access control, vendor risk assessments, and data segregation are essential.

Across these incidents, a few critical patterns emerge:

• Third-Party Risk: Vendors are often the weakest link.
• MFA Enforcement: Many breaches could have been stopped with properly enforced multi-factor authentication.
• Cloud Misconfigurations: Mismanaged credentials and lax permissions remain persistent problems.
• Dwell Time: Attackers are still spending weeks or months inside environments before detection.
• Reactive Security Postures: Far too many organizations are only discovering flaws post-breach.

While no security measure is a silver bullet, regular and targeted penetration testing plays a pivotal role in minimizing exposure:

• Simulates real-world attack paths before threat actors find them.
• Validates security controls like MFA, firewalls, and segmentation.
• Tests vendor and supply chain exposure through red teaming and lateral movement assessments.
• Assesses cloud infrastructure for misconfigurations and policy gaps.
• Improves response planning through tabletop exercises and post-exploitation scenarios.

The major breaches of the last three years have exposed a familiar pattern: critical systems left open, credentials reused or unprotected, and warning signs ignored. These incidents didn’t happen because attackers were exceptionally creative; they happened because basic defenses weren’t in place or weren’t tested under real pressure.

Security isn’t just about having tools in place. It’s about knowing how well those tools hold up when it counts. Penetration testing helps answer that question before someone else does.