Presenting one set of resources using different underlying resources.
Virtual machine
Environment presenting only authorized resources to a user class. User cannot formulate commands exposing unauthorized resources.
Hypervisor
Aka. virtual machine monitor.
Used for:
- Security isolation (e.g., two legal teams on same system).
- Legacy OS support.
- OS development/testing without target hardware.
- Protected virtual networks.
Sandbox
Environment limiting a process to controlled, bounded resources. Cannot affect outside resources.
- Java’s original design: local code = full access, remote applets = sandbox only.
- Java Virtual Machine serves as reference monitor.
- Weakness: opening sandbox for signed applets introduced vulnerabilities.
Honeypot
Faux environment luring attackers. Administrators monitor in real time. Attacker sees a controlled, limited view of actual system.