Data Breaches - Causes, Impact, and Response Steps

About 2 min read

A data breach is an incident in which confidential or personal information is exposed to unauthorized third parties. It can arise from many causes, including cyberattacks, insider misconduct, misconfigurations, and physical theft. The leaked data may include passwords, email addresses, credit card details, and medical records, making the damage severe. In a report published by IBM in 2024, the global average cost of a data breach was about 4.88 million USD, up 10% from the previous year, the largest yearly jump since the pandemic.

Real-World Use Cases

Real breaches often begin not with a dramatic attack but with the discovery of a misconfiguration. For example, an external security researcher gets in touch to say that a cloud storage bucket has been left publicly readable, and it turns out that files containing customer information were viewable by anyone. The first steps here are to turn off public access and restrict permissions, then check the access logs to see who actually retrieved what, and only then decide whether the incident must be reported to the data protection authority and disclosed to the individuals affected. Reporting obligations do not change just because the cause was a misconfiguration, so "we were not attacked, therefore it is not a breach" is not a defensible position.

Breach Response Workflow

Historical Background

Large-scale data breaches began to be recognized as a social issue from the 2010s onward. The 2013 Yahoo! incident leaked information on about 3 billion accounts, the largest breach in history. The 2017 Equifax incident exposed the credit information of about 147 million people, accelerating the debate over personal data protection in the United States. Triggered by these incidents, data protection legislation has been strengthened in many countries, beginning with the EU's GDPR (in force since 2018). In Japan as well, the 2022 amendment to the Act on the Protection of Personal Information tightened the obligation to report breaches.

Causes of Data Breaches

Cyberattacks such as SQL injection and phishing are the most common causes, but unintended public exposure due to cloud storage misconfigurations and insider misconduct by employees are far from rare. Breaches occurring through third-party services are also on the rise.

Responding to a Breach

If a data breach occurs at a service you use, changing your password promptly is the top priority. Generate a new, strong random password and change it not only on the breached service but also on any other services where you reused the same password. Checking your two-factor authentication settings and monitoring your credit card statements are also important.