The breach wasn't necessarily a complex hack but a critical oversight. A security researcher discovered that NPD had left a zip file—often identified as index_breached.vc.zip or similar variants—publicly accessible on their website. This file contained:
: Details on how their databases were structured and accessed. The Dark Web Leak
Experts later clarified that while the "2.9 billion" figure likely included many duplicates and deceased individuals, the scale remained historic. Unlike the , which stemmed from a software vulnerability, the NPD incident is frequently cited as a cautionary tale about directory listing vulnerabilities and the dangers of storing sensitive backups on internet-facing servers.
