It’s official—hack at Altos in California reveals patients’ personal and health information and forces free credit monitoring

September 24, 2025
It's official—hack at Altos in California reveals patients' personal and health information and forces free credit monitoring

With digitalization and the way hospitals, healthcare centers, and healthcare systems in general operate today, most patient data is stored on computers in massive databases. A hack has apparently compromised much of the personal data of patients in Altos, California. Based on the information available, an unauthorized third party may have accessed the data and deleted or exposed it.

The agency is alerting patients that their personal information may be involved in this hacking breach

Altos is a billing service provider for various healthcare providers in California, especially in the southern part of the state. The agency is alerting patients that their personal information may be involved in this hacking breach. This isn’t the first time something like this has happened. In August, a cyberattack on UnitedHealth Group’s technology unit, Change Healthcare, affected 192.7 million people, according to information posted on the U.S. Department of Health and Human Services website. The breach, which was first disclosed in February 2024, is considered the largest healthcare data breach in U.S. history.

An unprecedented crisis, given that a cyberattack of this magnitude can jeopardize the health of many people today

In the cyberattack we’re referring to, hackers identified as the “Blackcat” ransomware group infiltrated Change Healthcare’s systems, causing widespread disruptions in claims processing that affected patients and healthcare providers across the country. This could create an unprecedented crisis, given that a cyberattack of this magnitude can jeopardize the health of many people today. As we’ve seen, wars in the 21st century take many forms.

Altos immediately blocked access to the system and began an investigation

According to the information available so far, Altos discovered on June 17 that one of its internal systems, containing personal and health information, was exposed to the internet. After confirming the exposure, Altos immediately blocked access to the system and began an investigation. These types of breaches typically take months or even years to complete. Breaking into corporate databases, especially those of this type, is becoming increasingly difficult for hackers. In any case, once inside, they can steal, modify, or delete all types of information.

The exposed information included names, addresses, dates of birth, Social Security numbers, and patient medical information

The data that was exfiltrated was highly sensitive, as it included highly specific personal information about hundreds of patients. The investigation concluded on July 21, revealing that the exposed information included names, addresses, dates of birth, Social Security numbers, and patient medical information. Data breaches have become increasingly common in recent years, as we explained before, so security must be heightened, especially when dealing with data as specific as this. A cybersecurity firm hired by Altos concluded that an unauthorized third party had accessed the system and may have extracted the data referred to above.

Recommendation: It’s best to be precise because pension funds, savings, and life insurance can be put at risk

The company recommends contacting authorities as soon as you notice any signs of theft, fraud, or hacking. Altos advises affected patients to remain alert to incidents of fraud or identity theft, reviewing their account statements and credit reports for any unauthorized activity. It’s an arduous process for those affected, but it’s best to be precise because pension funds, savings, and life insurance can be put at risk. The company also provides instructions for activating fraud alerts or freezing credit on credit reports. In any case, if you have any questions, contact official sources.