27 Major Data Breaches Reveal Common Security Failures and Lessons for Defenders
Summary
A review of 27 major data incidents highlights recurring causes—including exposed databases, weak passwords, unpatched flaws, and compromised credentials—and recommends defenses such as MFA, encryption, patching, and security awareness training.
Key points
- The article distinguishes traditional breaches from accidental data leaks and large-scale scraping, which it says are often grouped together as data breaches.
- Many incidents stemmed from preventable weaknesses, including unsecured databases, misconfigurations, unpatched vulnerabilities, and weak password storage.
- Compromised employee or third-party credentials enabled access in several cases, including the eBay and Home Depot incidents.
- Exposed personal data can support phishing, identity theft, fraud, and credential-stuffing attacks, especially when people reuse passwords.
- The article recommends encrypting sensitive data, enabling MFA, applying software updates, using unique strong passwords, and providing security awareness training.
- It cites a 2025 survey of more than 500 US IT professionals: 26.4% said their organizations lose $100,000–$500,000 annually to cybercrime.
Article Details
- Topic
- Historical large-scale data breaches and the security lessons they offer
People
Threat Actors
Malware
Products
Apache Strutswas caused by the company's failure to patch a known vulnerability in their web application software, Apache Struts. Threat actors exploited this flaw undetected for more than two months to gain access to the company'sMicrosoft Exchange ServerIn early 2021, a series of cyberattacks exploited zero-day vulnerabilities in Microsoft Exchange Servers. Attackers, including the state-sponsored group Hafnium, gained full access to user data and administrative
Countries
Industries
Financial Servicesnumbers, or dates of birth, wasn’t compromised. The incident was a serious wake-up call for the financial industry, highlighting the need for robust security measures in an increasingly digital world.GamingIt’s not always fun and games for online gaming platform Zynga. The company behind popular mobile games like Words With Friends and Draw Something suffered a major data breach in 2019. A Pakistani threat actor claimedSocial mediaOne of China's largest social media platforms, Sina Weibo’s 2020 data breach exposed the personal information of over 538 million users. A threat actor advertised the user database for sale on the dark web, claiming to