**The Biggest Data Breaches of 2024: 1 Billion Stolen Records and Counting**

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We're halfway through 2024, and this year has already seen some of the most significant and damaging data breaches in recent history. The worst part? These breaches have already surpassed 1 billion stolen records, and the number is still rising.

From massive stores of customers' personal information being scraped, stolen, and posted online to reams of medical data covering most people in the United States being stolen, the impact of these breaches is far-reaching and devastating. Not only do they affect the individuals whose data was exposed, but they also embolden the criminals who profit from their malicious cyberattacks.

Let's take a look at some of the biggest security incidents of 2024, their impact, and how they could have been prevented.

Mystery AT&T Data Leak Exposed 73 Million Customer Accounts

In March, a data breach broker dumped the full cache of 73 million customer records online, including customers' personal information, such as names, phone numbers, and postal addresses. Some customers confirmed that their data was accurate. But it wasn't until a security researcher discovered that the exposed data contained encrypted passcodes used for accessing a customer's AT&T account that the telecoms giant took action. The security researcher found that the encrypted passcodes could be easily unscrambled, putting some 7.6 million existing AT&T customer accounts at risk of hijacks.

Change Healthcare Hackers Stole Medical Data on "Substantial Proportion" of Americans

In 2022, the U.S. Justice Department sued health insurance giant UnitedHealth Group to block its attempted acquisition of health tech giant Change Healthcare, fearing that the deal would give the healthcare conglomerate broad access to about "half of all Americans' health insurance claims" each year. The bid to block the deal ultimately failed. Then, two years later, something far worse happened: Change Healthcare was hacked by a prolific ransomware gang, and its almighty banks of sensitive health data were stolen because one of the company's critical systems was not protected with multi-factor authentication.

The lengthy downtime caused by the cyberattack dragged on for weeks, causing widespread outages at hospitals, pharmacies, and healthcare practices across the United States. But the aftermath of the data breach has yet to be fully realized, though the consequences for those affected are likely to be irreversible. UnitedHealth says the stolen data includes the personal, medical, and billing information on a "substantial proportion" of people in the United States.

Synnovis Ransomware Attack Sparked Widespread Outages at Hospitals Across London

A June cyberattack on U.K. pathology lab Synnovis caused ongoing widespread disruption to patient services for weeks. The local National Health Service trusts that rely on the lab postponed thousands of operations and procedures following the hack, prompting the declaration of a critical incident across the U.K. health sector.

A Russia-based ransomware gang was blamed for the cyberattack, which saw the theft of data related to some 300 million patient interactions dating back a "significant number" of years. Much like the data breach at Change Healthcare, the ramifications for those affected are likely to be significant and life-lasting.

Some of the data was already published online in an effort to extort the lab into paying a ransom. Synnovis reportedly refused to pay the hackers' $50 million ransom, preventing the gang from profiting from the hack but leaving the U.K. government scrambling for a plan in case the hackers posted millions of health records online.