Four Catastrophic Cybersecurity Data Breaches of 2024

Cybersecurity breaches have become an annual occurrence, with their severity increasing as technology advances and hackers refine their methods. In 2024, cyberattacks surged across sectors such as healthcare, finance, and critical infrastructure, resulting in unprecedented data compromises. According to IBM’s annual Cost of a Data Breach Report, the global average cost of a data breach reached a staggering $4.88 million (£3.9 million) in 2024—marking a 10% increase from the previous year and the largest annual jump since the pandemic. Notably, 70% of breached organizations reported experiencing significant or very significant disruption.

This article examines the most significant data breaches of 2024, detailing the attack methodologies, affected sectors, and the far-reaching consequences for both individuals and organizations.

AT&T Data Breach

In July 2024, AT&T, one of the largest telecom providers in the U.S., disclosed a massive data breach that compromised call and text records of approximately 109 million customers. The breach was traced to a vulnerability in the Snowflake cloud platform, a third-party service AT&T used for customer data storage.

Although the breach occurred in April 2024, it was not publicly revealed until July. AT&T delayed the announcement to comply with security protocols and coordinate with law enforcement. While the breach did not expose personal messages or call content, it did include customer phone numbers, contacts, and possible location data via cell tower IDs.

Following the announcement, AT&T confirmed that they had closed the unauthorized access point, engaged cybersecurity experts for investigation, and reported that at least one suspect had been apprehended.

National Public Data Breach

In August 2024, National Public Data (NPD), a major consumer data provider for background checks, confirmed a large-scale data breach affecting around 2.9 billion personal records. The compromised data included names, addresses, emails, phone numbers, and Social Security numbers of individuals in the U.S., U.K., and Canada.

The breach was linked to the hacker group USDoD, which initially accessed the data in late December 2023 and later attempted to sell it on the dark web in April 2024 for $3.5 million. The incident remained under the radar until August when a California resident, alerted by his identity theft protection service, filed a class-action lawsuit.

Following public exposure, NPD acknowledged the breach, took immediate steps to mitigate the damage, and collaborated with law enforcement agencies to investigate and prevent further breaches.

Dell Data Breach

In May 2024, Dell notified customers of a significant data breach that exposed personal information, including customer names, home addresses, and details about Dell hardware and orders, such as service tags, item descriptions, order dates, and warranty details.

Although Dell did not specify the cause, reports surfaced of a hacker attempting to sell data from the breach on an online forum. The attacker claimed to have accessed records belonging to 49 million Dell customers across multiple countries, including the U.S., China, India, Australia, and Canada.

Dell assured customers that the breach did not include sensitive information such as email addresses, phone numbers, or financial details. The company advised users to report any suspicious activity related to their Dell accounts.

Change Healthcare Ransomware Attack

The Change Healthcare breach is considered the largest theft of U.S. medical records and one of the most significant data breaches in history.

In late February 2024, the Russian-speaking cybercriminal group Blackcat (Alphv) attacked Change Healthcare, a major U.S. healthcare payment processor. The hackers stole an estimated 4 terabytes of data, including personal details, payment information, insurance records, and medical histories.

The attack disrupted operations for weeks, preventing pharmacies, hospitals, and healthcare providers from processing claims and receiving payments. In response, a $22 million ransom was paid in March, but it failed to ensure the recovery of stolen data or restore full functionality.

In April 2024, UnitedHealth Group, Change Healthcare’s parent company, publicly acknowledged the breach. Investigations revealed that the attack exploited a critical vulnerability—the lack of multi-factor authentication (MFA) on a Citrix portal—allowing hackers unauthorized access to the system.

Key Takeaways

These major data breaches underscore the growing importance of robust cybersecurity measures. Organizations must invest in advanced threat detection technologies, enforce strict access controls, and implement comprehensive employee cybersecurity training to safeguard sensitive data and reduce breach impacts.