The correct answer is least privilege, because the logs reveal that root SSH access is enabled, allowing a brute force attack to target the most privileged account on the system. The principle of least privilege dictates that users and services should only have the minimum permissions necessary to perform their tasks, and granting root the ability to log in remotely via SSH directly violates this by exposing a high-value target to repeated authentication failures. On the ISC2 Certified in Cybersecurity CC exam, this scenario tests your ability to identify which security principle is most directly compromised when a specific control—like disabling root SSH—is missing; a common trap is to confuse this with defense in depth, which would be violated only if no additional layers of security existed. Remember the memory tip: “Root remote access? That’s a least privilege mess.”
ISC2 CC Security Principles Practice Question
This CC practice question tests your understanding of security principles. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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.
Exhibit
Refer to the exhibit.
```
May 12 10:00:00 server sshd[1234]: Failed password for root from 192.168.1.10 port 22 ssh2
May 12 10:00:05 server sshd[1234]: Failed password for root from 192.168.1.10 port 22 ssh2
May 12 10:00:10 server sshd[1234]: Failed password for root from 192.168.1.10 port 22 ssh2
May 12 10:00:15 server sshd[1235]: Accepted password for admin from 10.0.0.5 port 22 ssh2
```
The exhibit shows a snippet of /var/log/auth.log on a Linux server. Which security principle is most likely violated if the failed attempts continue without action?
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.
Refer to the exhibit.
```
May 12 10:00:00 server sshd[1234]: Failed password for root from 192.168.1.10 port 22 ssh2
May 12 10:00:05 server sshd[1234]: Failed password for root from 192.168.1.10 port 22 ssh2
May 12 10:00:10 server sshd[1234]: Failed password for root from 192.168.1.10 port 22 ssh2
May 12 10:00:15 server sshd[1235]: Accepted password for admin from 10.0.0.5 port 22 ssh2
```
A
Non-repudiation
Why wrong: Non-repudiation ensures actions cannot be denied; the logs already provide that.
B
Separation of duties
Why wrong: Separation of duties is about dividing roles, not about remote access.
C
Least privilege
Allowing root login over SSH grants full privileges and is a violation of least privilege; it should be disabled.
D
Defense in depth
Why wrong: While lacking other controls, the specific violation is allowing root SSH access.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Least privilege
The logs show repeated failed SSH attempts from the same IP, indicating a brute force attack. If no action is taken, availability could be compromised if the attacker locks out the root account, or confidentiality/integrity if they succeed. However, most directly, the principle of least privilege is violated because root login over SSH is allowed (root is a privileged account). Option A is correct. Option B (defense in depth) would be violated if no other controls, but the question asks the principle most likely violated. Option C (separation of duties) not relevant. Option D (non-repudiation) not directly.
Key principle: Authentication proves identity; authorization controls what that identity can do after login. Both must work for full privileged access.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Non-repudiation
Why it's wrong here
Non-repudiation ensures actions cannot be denied; the logs already provide that.
✗
Separation of duties
Why it's wrong here
Separation of duties is about dividing roles, not about remote access.
✓
Least privilege
Why this is correct
Allowing root login over SSH grants full privileges and is a violation of least privilege; it should be disabled.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Authentication checks who the user is.
✗
Defense in depth
Why it's wrong here
While lacking other controls, the specific violation is allowing root SSH access.
Common exam traps
Common exam trap: authentication is not authorization
Logging in proves the user can authenticate. It does not automatically mean the user is allowed to enter privileged or configuration mode. Watch for AAA authorization, privilege level and command authorization details.
Detailed technical explanation
How to think about this question
This kind of question is testing the difference between identity and permission. A user may successfully log in to a router because authentication is working, but still fail to enter configuration mode because authorization is missing, misconfigured or mapped to a lower privilege level.
KKey Concepts to Remember
Authentication checks who the user is.
Authorization controls what the user is allowed to do after login.
Privilege levels affect access to EXEC and configuration commands.
AAA, TACACS+ and RADIUS can separate login success from command access.
TExam Day Tips
→Do not assume successful login means full administrative access.
→Look for words such as cannot enter configuration mode, privilege level, authorization or command access.
→Separate login problems from permission problems before choosing the answer.
Key takeaway
Authentication proves identity; authorization controls what that identity can do after login. Both must work for full privileged access.
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. Authentication proves identity; authorization controls what that identity can do after login. Both must work for full privileged access. 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 CC question in full detail.
Review Cisco AAA concepts — authentication, authorization, and accounting. Study privilege levels (0–15), command authorization under TACACS+, and how RADIUS differs. Then practise related CC questions on access control and AAA configuration.
Security Principles — This question tests Security Principles — Authentication checks who the user is..
What is the correct answer to this question?
The correct answer is: Least privilege — The logs show repeated failed SSH attempts from the same IP, indicating a brute force attack. If no action is taken, availability could be compromised if the attacker locks out the root account, or confidentiality/integrity if they succeed. However, most directly, the principle of least privilege is violated because root login over SSH is allowed (root is a privileged account). Option A is correct. Option B (defense in depth) would be violated if no other controls, but the question asks the principle most likely violated. Option C (separation of duties) not relevant. Option D (non-repudiation) not directly.
What should I do if I get this CC question wrong?
Review Cisco AAA concepts — authentication, authorization, and accounting. Study privilege levels (0–15), command authorization under TACACS+, and how RADIUS differs. Then practise related CC questions on access control and AAA configuration.
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?
Authentication checks who the user is.
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