CREST Practitioner Security Analyst (CPSA) Practice

What is the correct representation for read-only permission in Linux file permissions format?

1. r-x

2. ---

3. rw-

4. rwx

The correct answer is: r-x

In Linux file permissions, the representation for read-only permission is characterized by having the read permission for the user or group, while denying both write and execute permissions. The correct representation for read-only permission is depicted as "r--," indicating that the user can read the file but cannot modify it or execute it. The option that indicates read-only permission should show only the read flag as active, while both write and execute flags should be off. The provided answer is "r-x," which includes execute permission (x) as well, which makes it incorrect for a strict read-only representation. The correct format to signify read-only would simply be "r--" instead. Understanding the structure of permissions is essential: the first character denotes the read permission, the second character denotes the write permission, and the third denotes the execute permission. Therefore, for read-only access, the ideal configuration would exclude both write and execute options, focusing solely on the read function.