XK0-006 Security Practice Question
A Linux administrator needs to ensure that all user passwords meet a minimum length of 12 characters and include at least one uppercase letter, one lowercase letter, one digit, and one special character. Which file should be edited to enforce these password complexity requirements?
⚠ Common exam trap
The trap here is assuming that /etc/login.defs handles all password policies, but it only covers aging and minimum length, not character complexity.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
/etc/security/pwquality.conf
Password complexity requirements are enforced by the pam_pwquality module, which reads its configuration from /etc/security/pwquality.conf. This file allows setting parameters like minlen, ucredit, lcredit, dcredit, and ocredit to require specific character types and lengths. The other files serve different purposes and cannot enforce these rules.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
/etc/security/pwquality.conf
Why this is correct
The /etc/security/pwquality.conf file is used by the pam_pwquality module to enforce password complexity rules such as minimum length (minlen), required character classes (ucredit, lcredit, dcredit, ocredit), and other checks. Editing this file allows the administrator to set these requirements system-wide for all users, ensuring compliance with the security policy.
- ✗
/etc/pam.d/system-auth
Why it's wrong here
/etc/pam.d/system-auth is a PAM configuration file that controls authentication modules. While it may include the pam_pwquality module, editing it directly to set complexity parameters is not the standard method. The pam_pwquality module reads its settings from /etc/security/pwquality.conf, so changes should be made there. Modifying system-auth could affect authentication flow and is not the recommended place for password policy settings.
- ✗
/etc/login.defs
Why it's wrong here
/etc/login.defs contains configuration for login behavior, such as password aging (PASS_MAX_DAYS), UID/GID ranges, and umask, but it does not enforce password complexity rules like character classes. While it can set a minimum password length via PASS_MIN_LEN, it cannot require uppercase, lowercase, digits, or special characters. Therefore, it is insufficient for the stated requirements.
- ✗
/etc/shadow
Why it's wrong here
/etc/shadow stores encrypted user passwords and password aging information, but it does not contain policy settings for complexity. Editing this file would not enforce any rules; it only holds per-user data. Password complexity must be enforced through PAM modules that check passwords at change time, configured via pwquality.conf or similar.
Go deeper
Related to this question
Learn chapter
Networking Fundamentals and Configuration
Key term
User
A user is any person, system, or device that interacts with an IT service, resource, or identity system, typically authenticated through credentials and authorized to perform specific actions.
Key term
Linux
Linux is an open-source operating system that manages computer hardware and software, widely used in servers, desktops, and embedded systems.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This XK0-006 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the XK0-006 exam.