- A
The administrator configured 'port-security maximum 1' but forgot to enable 'port-security' globally.
Why wrong: If global port-security is not enabled, the command has no effect, but the configuration is present; this is less likely than MAC spoofing.
- B
The switchport security violation mode is set to 'shutdown' instead of 'restrict'.
Why wrong: Shutdown mode would disable the port upon violation, not allow access.
- C
The switchport uses sticky MAC learning, and the attacker used a MAC spoofing attack to mimic an authorized device.
Sticky MAC learns the first MAC; spoofing that MAC allows access.
- D
The switchport is configured as an access port but the rogue device is using a VLAN trunk.
Why wrong: Trunking on an access port may be possible but port security still enforces MAC limits; not the primary weakness.
Quick Answer
The correct answer is that the switchport uses sticky MAC learning, and the attacker bypassed port security through MAC spoofing. Sticky MAC dynamically records the first MAC address it sees on a port and locks that address as the only allowed device, but it does not validate whether subsequent traffic actually originates from that same physical hardware. An attacker can simply sniff the network to discover an authorized MAC address, then configure their rogue device to spoof that address, causing the switch to treat the impersonating traffic as legitimate and grant access. On the ISC2 Certified in Cybersecurity CC exam, this scenario tests your understanding that port security alone is a layer-2 control vulnerable to spoofing, especially when sticky MAC is used without 802.1X or MAB. A common trap is assuming sticky MAC prevents all unauthorized access, but it only prevents new, unknown MACs—not cloned ones. Memory tip: Sticky MAC is like a bouncer who checks a photo ID but never looks at the person’s face.
ISC2 CC Network Security Practice Question
This CC practice question tests your understanding of network security. 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.
During a penetration test, an analyst discovers that a company's internal network has a switch configured with port security that allows only one MAC address per port. However, the analyst is able to plug a rogue device into a wall jack and successfully gain network access. What is the most likely weakness in this configuration?
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.
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
The switchport uses sticky MAC learning, and the attacker used a MAC spoofing attack to mimic an authorized device.
Option C is correct because port security with sticky MAC learning records the first MAC address seen on a port and then restricts access to that address only. However, if an attacker spoofs the MAC address of an already-authorized device, the switch sees the spoofed MAC as valid and permits access, bypassing the one-MAC-per-port restriction. This is a common bypass when sticky MAC is used without additional protections like 802.1X or MAC authentication bypass (MAB).
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 administrator configured 'port-security maximum 1' but forgot to enable 'port-security' globally.
Why it's wrong here
If global port-security is not enabled, the command has no effect, but the configuration is present; this is less likely than MAC spoofing.
- ✗
The switchport security violation mode is set to 'shutdown' instead of 'restrict'.
Why it's wrong here
Shutdown mode would disable the port upon violation, not allow access.
- ✓
The switchport uses sticky MAC learning, and the attacker used a MAC spoofing attack to mimic an authorized device.
Why this is correct
Sticky MAC learns the first MAC; spoofing that MAC allows access.
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 switchport is configured as an access port but the rogue device is using a VLAN trunk.
Why it's wrong here
Trunking on an access port may be possible but port security still enforces MAC limits; not the primary weakness.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the misconception that 'port-security maximum 1' alone prevents any unauthorized device, but the trap here is that sticky MAC learning does not prevent MAC spoofing—it only restricts the number of unique MACs, not the identity of the device using that MAC.
Trap categories for this question
Command / output trap
If global port-security is not enabled, the command has no effect, but the configuration is present; this is less likely than MAC spoofing.
Detailed technical explanation
How to think about this question
Sticky MAC learning stores dynamically learned MAC addresses into the running configuration as static secure MAC entries. If an attacker spoofs an authorized MAC, the switch treats the frame as valid because the source MAC matches a secure entry, and no violation is triggered. In real-world scenarios, this can be mitigated by combining port security with 802.1X or by using 'port-security mac-address' with manually configured addresses and disabling sticky learning.
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.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this CC question test?
Network Security — This question tests Network Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The switchport uses sticky MAC learning, and the attacker used a MAC spoofing attack to mimic an authorized device. — Option C is correct because port security with sticky MAC learning records the first MAC address seen on a port and then restricts access to that address only. However, if an attacker spoofs the MAC address of an already-authorized device, the switch sees the spoofed MAC as valid and permits access, bypassing the one-MAC-per-port restriction. This is a common bypass when sticky MAC is used without additional protections like 802.1X or MAC authentication bypass (MAB).
What should I do if I get this CC 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.
About these practice questions
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Last reviewed: Jun 30, 2026
This CC practice question is part of Courseiva's free ISC2 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 CC exam.
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