The answer is that the user's account is locked due to multiple failed attempts. This RADIUS account lockout pattern—successful authentications followed by failures—indicates the user initially entered the correct password, but subsequent incorrect attempts triggered a security threshold, locking the account and rejecting even valid credentials. On the CISSP exam, this scenario tests your understanding of authentication controls within the Identity and Access Management (IAM) domain, specifically how account lockout policies mitigate brute-force attacks. A common trap is assuming the failures stem from a password change or server error, but the key is the sequence: successes prove the password was correct, then lockout causes the failures. Remember the memory tip: “Success then fail means lockout’s the tale.”
CISSP Identity and Access Management Practice Question
This CISSP practice question tests your understanding of identity and access management. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
Refer to the exhibit. A RADIUS server log shows multiple successful authentications for the same user followed by failures. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
The user's account is locked due to multiple failed attempts
After several failed attempts, the account lockout policy triggers, causing subsequent failures. The earlier successes may be from another session or before lockout.
B
The user's password has expired
Why wrong: Password expiration would cause failure on first attempt after expiry, not several successes followed by failures.
C
The RADIUS server is misconfigured with a wrong secret
Why wrong: A misconfiguration would cause all authentications from that client to fail, not a mix.
D
The user is a victim of credential stuffing
Why wrong: Credential stuffing would show many failures with different usernames or passwords, not a single user with successes then failures.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The user's account is locked due to multiple failed attempts
The RADIUS log shows successful authentications followed by failures for the same user. This pattern indicates that the user's password was correct initially, but subsequent failures triggered an account lockout policy. Account lockout is a common security control that disables an account after a threshold of failed attempts, preventing further authentication even with the correct password.
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 user's account is locked due to multiple failed attempts
Why this is correct
After several failed attempts, the account lockout policy triggers, causing subsequent failures. The earlier successes may be from another session or before lockout.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The user's password has expired
Why it's wrong here
Password expiration would cause failure on first attempt after expiry, not several successes followed by failures.
✗
The RADIUS server is misconfigured with a wrong secret
Why it's wrong here
A misconfiguration would cause all authentications from that client to fail, not a mix.
✗
The user is a victim of credential stuffing
Why it's wrong here
Credential stuffing would show many failures with different usernames or passwords, not a single user with successes then failures.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse account lockout with password expiry or credential stuffing, but the specific sequence of successes followed by failures uniquely points to lockout, not a global authentication failure.
Trap categories for this question
Command / output trap
Credential stuffing would show many failures with different usernames or passwords, not a single user with successes then failures.
Detailed technical explanation
How to think about this question
RADIUS uses the User-Password attribute (RADIUS Attribute 2) encrypted with the shared secret and MD5 hash. Account lockout is enforced by the NAS or the RADIUS server itself, often via a directory service like Active Directory, which increments the badPwdCount attribute and locks the account when it exceeds the lockout threshold. The log pattern of successes then failures is a classic indicator of lockout, as the user's correct password is rejected once the account is disabled.
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: The user's account is locked due to multiple failed attempts — The RADIUS log shows successful authentications followed by failures for the same user. This pattern indicates that the user's password was correct initially, but subsequent failures triggered an account lockout policy. Account lockout is a common security control that disables an account after a threshold of failed attempts, preventing further authentication even with the correct password.
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.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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