Virtual Ghosts

Censys presents a method to detect "Virtual Ghosts": web servers that still serve content for DNS names that no longer resolve, due to stale virtual-host configurations. Using name-based scans and historical snapshots, they identified hundreds of instances (including admin panels and directory listings) where removed DNS entries still map to accessible content, explaining the detection methodology, measurement results from random and targeted samples, and recommending tracking such assets via their Web Entities feature to reduce exposure.