A Year of Digital Disruption: The Top Cyber Attacks of 2024

The year 2024 will be remembered as a watershed moment in cybersecurity, a period when digital threats escalated from background noise to front-page news. Across the globe, critical infrastructure was crippled, sensitive data of hundreds of millions was exposed, and the intricate connections that power our modern world were exploited on an unprecedented scale. From crippling ransomware attacks on healthcare systems to sophisticated state-sponsored espionage, these events were more than just technical failures; they were profound disruptions to daily life. Here’s a look at the ten most significant cyber attacks that defined a year of digital disruption.

1. Change Healthcare: The Ransomware Attack That Paralyzed U.S. Healthcare

In a stark demonstration of how vulnerable critical infrastructure has become, the ransomware attack on Change Healthcare sent shockwaves through the entire U.S. healthcare system. Wielded by the BlackCat/ALPHV group, the attack crippled a company responsible for processing half of all medical claims in the country. Pharmacies were unable to verify insurance, doctors couldn't get paid, and patient care was delayed. The breach not only resulted in billions of dollars in losses for its parent company, UnitedHealth Group, but also compromised the personal data of a massive portion of the American population, marking one of the most disruptive cyberattacks in history.

2. Snowflake: A Cascade of Breaches from a Single Point of Weakness

The Snowflake incident was a unique and devastating lesson in cloud security. Rather than a direct breach of Snowflake's core systems, cybercriminals targeted the accounts of its customers who had failed to enable multi-factor authentication. A hacking group, believed to be UNC5537, exploited this weakness to siphon enormous volumes of data from household names like Live Nation (Ticketmaster) and Santander Bank. The attack created a domino effect of breaches and served as a critical reminder of the shared responsibility model in cybersecurity—a powerful platform is only as secure as its weakest user.

3. AT&T: A Double Blow for a Telecom Giant

AT&T endured a brutal year, suffering two massive data breaches that affected millions. In one devastating incident, the personal data of over 73 million current and former customers, including social security numbers, was leaked onto the dark web. As if that weren't enough, a separate breach linked to the Snowflake attack exposed the call and messaging metadata of 110 million customers. The events forced a massive password reset and laid bare the immense vulnerabilities of holding vast, centralized customer databases.

4. CrowdStrike: When the Cure Becomes the Cause

In a startling "friendly fire" incident, a flawed software update from cybersecurity firm CrowdStrike caused global chaos. The update for its widely used Falcon sensor triggered the infamous "Blue Screen of Death" on Windows machines worldwide. Airlines grounded flights, businesses halted operations, and government services were disrupted. While not a malicious attack, the outage had the same impact as one, demonstrating the immense risk of supply chain vulnerabilities and highlighting the fact that even the tools meant to protect us can become a single point of failure.

5. Salt Typhoon: A Nation-State Threat Lurking in the Shadows

It was revealed in 2024 that a Chinese state-sponsored hacking group dubbed "Salt Typhoon" had been quietly infiltrating U.S. critical infrastructure for years. The group had burrowed deep into telecommunications, energy, and water systems, not to cause immediate damage, but to pre-position itself for potential future disruptive attacks. The discovery was a chilling reminder of the long-term, stealthy nature of nation-state threats and raised significant national security concerns about the resilience of essential services.

6. & 7. MediSecure and Ascension: Healthcare Under Siege

The assault on the healthcare sector didn't stop with Change Healthcare. In Australia, e-script provider MediSecure was hit by a major ransomware attack that exposed millions of electronic prescriptions, stoking public fear about the security of digital health records. In the U.S., Ascension, one of the nation's largest non-profit health systems, had its clinical operations across 142 hospitals paralyzed by ransomware. These attacks, targeting the most vulnerable, painted a clear picture of a sector under constant siege.

8. Ivanti: The Peril of the Zero-Day Exploit

The year kicked off with threat actors exploiting multiple "zero-day" vulnerabilities in Ivanti's widely used remote access software. Before a patch was even available, attackers used these flaws as a gateway into the networks of countless organizations, including government agencies and major corporations. The incident highlighted the frantic race between attackers and defenders and underscored the significant risk posed by undiscovered flaws in enterprise software.

9. UK Ministry of Defence: A Breach at the Heart of National Security

A cyberattack on a third-party payroll system used by the UK's Ministry of Defence exposed the names and bank details of current and former armed forces personnel. While the MoD stated no data was stolen, the breach was a serious national security concern. It pointed to the vulnerability of government supply chains and the ever-present threat of state-sponsored actors seeking to gather intelligence or cause disruption.

10. loanDepot: A Financial Shakedown

One of America's largest mortgage lenders, loanDepot, was brought to its knees by a ransomware attack that compromised the data of nearly 17 million customers and disrupted operations. Customers were unable to make payments or access their accounts, and the breach of sensitive financial data put millions at risk of fraud. The attack served as a potent wake-up call for the financial sector about the tangible and immediate impact of cybercrime on both businesses and consumers.