Process and analysis
What is Asset inventory?
The maintained list of systems an organisation owns, without which nobody can say what is exposed.
An asset inventory is the maintained list of systems, applications, accounts and services an organisation owns or runs. It sounds administrative, but every security question that starts with "are we affected?" depends on it.
The useful inventory records more than hostnames. It notes the software and version on each system, who owns it, whether it faces the internet and how critical it is. Without that, a vulnerability advisory or a threat report cannot be mapped to anything real.