The answer is that the ACL is misconfigured because the permit any at the end overrides the deny statements. This occurs due to the fundamental ACL processing order: Cisco ACLs evaluate rules sequentially from top to bottom, and as soon as a packet matches a rule, processing stops. Since the permit any is placed last, it matches all traffic that hasn’t already been permitted, meaning the preceding deny statements for the specific subnet are never reached, effectively bypassing the intended restriction. On the CISA exam, this scenario tests your understanding of access control logic and common misconfigurations that create security gaps—auditors must spot when a broad permit rule undermines granular denies. A frequent trap is assuming deny rules are evaluated regardless of order, but the sequential nature means the last rule wins for unmatched traffic. Memory tip: think “first match wins, last rule catches all”—if a permit any sits at the bottom, it swallows every deny above it.
CISA Protection of Information Assets Practice Question
This CISA practice question tests your understanding of protection of information assets. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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
Access Control List (ACL) applied to interface GigabitEthernet0/0:
permit ip host 10.0.0.1 any
deny ip 10.0.0.0/24 any
permit ip any any
Refer to the exhibit. An auditor reviews the ACL and notes that it allows traffic from a specific host while blocking other IPs in the same subnet. What is the most likely security issue?
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 the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The ACL is misconfigured because the permit any at the end bypasses the deny.
Option B is correct because the ACL has a 'permit any' statement at the end, which overrides the preceding 'deny' statements. In Cisco ACLs, packets are processed sequentially from top to bottom; once a match is found, no further rules are evaluated. Therefore, the 'deny' for the subnet is never reached, and all traffic (including from the blocked subnet) is permitted, defeating the intended restriction.
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 ACL blocks all traffic from the subnet except the host, which is desired.
Why it's wrong here
The desired effect is not achieved because the final permit any allows all traffic.
✓
The ACL is misconfigured because the permit any at the end bypasses the deny.
Why this is correct
Correct. The permit any at the end makes the deny rule redundant, allowing all traffic from the subnet.
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 ACL allows all traffic from the specific host, which is a risk.
Why it's wrong here
While allowing a specific host can be a risk, the greater issue is that the deny is bypassed.
✗
The ACL should be reversed to deny first.
Why it's wrong here
Reversing the order would still have issues; the permit any should be removed or restricted.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume that a 'deny' statement earlier in the ACL will block traffic regardless of later 'permit any' statements, but Cisco ACLs process rules sequentially and the first match wins, so the 'permit any' overrides the deny.
Detailed technical explanation
How to think about this question
Cisco ACLs use first-match logic: a packet is compared against each entry in order, and the first matching entry's action (permit or deny) is applied. The 'permit any' at the end acts as a catch-all, allowing all traffic not explicitly denied earlier. In this scenario, the 'deny' for the subnet is placed before the 'permit any', but because the 'permit any' matches all remaining traffic, the deny is effectively ignored for any traffic that does not match earlier permit statements. This is a common misconfiguration when administrators assume that a deny rule will block traffic even if a later permit any exists.
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 administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Protection of Information Assets — This question tests Protection of Information Assets — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The ACL is misconfigured because the permit any at the end bypasses the deny. — Option B is correct because the ACL has a 'permit any' statement at the end, which overrides the preceding 'deny' statements. In Cisco ACLs, packets are processed sequentially from top to bottom; once a match is found, no further rules are evaluated. Therefore, the 'deny' for the subnet is never reached, and all traffic (including from the blocked subnet) is permitted, defeating the intended restriction.
What should I do if I get this CISA 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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