The lesson's warning permits students to use the demonstrated techniques against real systems as long as they do not change any files.

### Why this is right The lesson explicitly restricts the exercise to the class's virtual-machine environment and warns that using the techniques on people, companies, or institutions without permission can lead to serious consequences. Avoiding file changes does not make unauthorized access permissible. ### The concept Authorization is a boundary, not a judgment based only on whether damage occurred. Reading files can expose confidential information even when nothing is modified. Scanning or exploiting a system without permission can also disrupt services or violate laws and institutional rules. The lesson uses Kali Linux and Metasploitable 2 as lab virtual machines on a host-only network so that students can observe security effects in a controlled setting. That setup does not grant permission to test unrelated systems. Students should follow the instructor's scope and stop if a target is not explicitly included in the exercise. Ethical security testing requires permission before the activity, not only an intention to avoid harm. ### The other options - **True**: This is wrong because the warning does not create a no-damage exception. Unauthorized file reading can itself compromise confidentiality and can still be unlawful or against institutional rules. ### Terms - **Authorization**: Explicit permission to perform a defined security test. - **Kali Linux**: A Linux distribution used in the lesson as the security-testing virtual machine. - **Metasploitable 2**: The deliberately vulnerable virtual machine used as the lab target in the lesson. - **Host-only network**: A virtual network configuration intended to keep virtual-machine traffic within the host environment. - **Confidentiality**: Protection of information against unauthorized access or disclosure. ### Remember Permission is required even when a test only reads data and causes no visible damage.