Changing the contents of a file without authorization is an attack on Integrity in the Confidentiality, Integrity, and Availability (CIA) model.

### Why this is right Integrity is the security goal concerned with keeping data accurate, complete, and unaltered unless a permitted change is made. An unauthorized file change directly violates that goal. ### The concept A security incident is classified by its effect. Reading a protected file without permission exposes information and harms confidentiality. Changing a file, including changing account data so a user can no longer log in, harms integrity because the stored information no longer has its authorized state. Preventing a user from logging in may also affect availability, depending on the impact, but the lesson's example focuses on the unauthorized alteration itself. Shutting down a system is the clearer availability example because it prevents authorized use of a resource. These categories help defenders explain which protection failed and what needs repair. A file modification can be accidental or malicious; in either case, integrity controls aim to detect or prevent unauthorized changes. ### The other options - **False**: This would be incorrect because it would classify an unauthorized alteration as something other than an integrity impact. It may be tempting to focus on whether the file is still readable, but the defining feature here is that its contents changed. ### Watch out Do not classify an incident only by the tool or person involved. Classify the consequence: exposure, alteration, or loss of access. ### Terms - **Integrity**: The property that information remains accurate, complete, and free from unauthorized alteration. - **CIA**: Confidentiality, Integrity, and Availability, the three security goals used in this lesson. - **Availability**: The ability of authorized users to access a system or information when needed. ### Remember Unauthorized alteration is an integrity impact, even when the altered file remains accessible.