The correct answer is that users are locked out after 5 failed login attempts and automatically unlocked after 5 minutes. This is because pam_tally2.so with deny=5 increments a failure counter on each unsuccessful authentication, and once the counter reaches 5, the account is locked to prevent further access. The unlock_time=300 parameter then sets a timer of 300 seconds, or 5 minutes, after which the counter is automatically reset and the account is unlocked. On the CISSP exam, this configuration tests your understanding of PAM account lockout policies as a technical control against brute-force attacks, often appearing in domain access control or security operations questions. A common trap is confusing seconds with minutes—remember that unlock_time is always in seconds, so 300 equals 5 minutes, not 5 hours. For a quick memory tip, think of the mnemonic “5-5-5”: 5 denials, 5 minutes, and 5 seconds per minute (300 total).
CISSP Identity and Access Management Practice Question
This CISSP practice question tests your understanding of identity and access management. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Users are locked out after 5 failed login attempts, and automatically unlocked after 5 minutes
Option C is correct because pam_tally2.so with deny=5 locks the user account after 5 failed authentication attempts, and unlock_time=300 sets the automatic unlock period to 300 seconds (5 minutes). This is a standard PAM (Pluggable Authentication Modules) configuration for account lockout policies, commonly used on Linux systems to mitigate brute-force attacks.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
The account is disabled after 5 successful logins
Why it's wrong here
It counts failed logins, not successful.
✗
Passwords must be changed every 5 days
Why it's wrong here
This configuration does not enforce password changes.
✓
Users are locked out after 5 failed login attempts, and automatically unlocked after 5 minutes
Why this is correct
deny=5 means lock after 5 failures; unlock_time=300 means 300 seconds (5 minutes).
Related concept
Read the scenario before looking for a memorised answer.
✗
Users are locked out after 5 failed attempts until manually unlocked
Why it's wrong here
The unlock_time parameter provides automatic unlocking.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse pam_tally2.so with password aging or account disablement features, or assume that unlock_time=300 means manual unlock is required, when in fact it specifies automatic unlock after 300 seconds.
Detailed technical explanation
How to think about this question
Under the hood, pam_tally2.so maintains a counter in a file (typically /var/log/tallylog) for each user; after deny=5 failures, the module returns PAM_AUTH_ERR and the account is locked until the unlock_time expires or an administrator resets the counter with pam_tally2 --reset. A subtle behavior is that the lockout applies per-service (e.g., SSH vs. console) unless configured globally, and the counter resets on successful authentication by default. In a real-world scenario, this protects against online brute-force attacks on SSH, but attackers may bypass it by using multiple IPs or slow attacks below the threshold.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CISSP question in full detail.
Identity and Access Management — This question tests Identity and Access Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Users are locked out after 5 failed login attempts, and automatically unlocked after 5 minutes — Option C is correct because pam_tally2.so with deny=5 locks the user account after 5 failed authentication attempts, and unlock_time=300 sets the automatic unlock period to 300 seconds (5 minutes). This is a standard PAM (Pluggable Authentication Modules) configuration for account lockout policies, commonly used on Linux systems to mitigate brute-force attacks.
What should I do if I get this CISSP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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