File notification is an event signal that tells software when a file has changed. Operating systems expose these alerts so apps can rescan folders, sync data, update backups, or trigger automation without constantly polling the disk. Common examples include create, modify, rename, and delete events.
In cyber security, file notifications matter because they can leak metadata even when file contents stay private. Repeated alerts may reveal when a user is typing, browsing, or exchanging media, creating a timing side channel that helps an observer infer activity patterns. Defenders should treat high-frequency file events as sensitive, limit unnecessary exposure of filesystem telemetry, and design apps to collect only the events they truly need. Attackers may also abuse these signals to fingerprint behavior or improve surveillance without direct file access.