The answer is that unrestricted traffic allowed after a specific deny is the most likely security risk. This occurs because a firewall processes rules sequentially from top to bottom, and a 'permit ip any any' rule placed at the end of the rule set will match and allow all traffic, effectively overriding any earlier deny statements designed to block specific threats. On the Certified Information Systems Auditor CISA exam, this scenario tests your understanding of firewall rule order as a critical control weakness, often presented in an exhibit showing a misconfigured access control list where a broad permit follows a narrow deny. A common trap is focusing on the content of the deny rule itself rather than its position relative to the permit any any. Remember the memory tip: "First match wins, so a late permit kills the early block."
CISA Governance and Management of IT Practice Question
This CISA practice question tests your understanding of governance and management of it. 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
Refer to the exhibit.
```
access-list 101 permit tcp any host 192.168.1.100 eq 80
access-list 101 permit tcp any host 192.168.1.100 eq 443
access-list 101 deny ip any host 192.168.1.100
access-list 101 permit ip any any
```
Based on the exhibit, what is the MOST likely security risk?
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.
```
access-list 101 permit tcp any host 192.168.1.100 eq 80
access-list 101 permit tcp any host 192.168.1.100 eq 443
access-list 101 deny ip any host 192.168.1.100
access-list 101 permit ip any any
```
A
The web server is fully protected
Why wrong: The final rule allows all traffic, so protection is bypassed.
B
Traffic to port 80 is not encrypted
Why wrong: Encryption is not addressed by ACL.
C
Unrestricted traffic is allowed after the specific deny
The permit any any allows all traffic, making the deny ineffective.
D
The host 192.168.1.100 is exposed to denial-of-service attacks
Why wrong: While possible, the immediate risk is the blanket permit rule.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Unrestricted traffic is allowed after the specific deny
Option C is correct because the 'permit ip any any' at the end allows all traffic, bypassing earlier specific denials. Option A is not correct because the deny line only blocks other traffic, but the permit any any overrides it. Option B is not directly indicated. Option D is a risk but less direct than the rule order issue.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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 web server is fully protected
Why it's wrong here
The final rule allows all traffic, so protection is bypassed.
Unrestricted traffic is allowed after the specific deny
Why this is correct
The permit any any allows all traffic, making the deny ineffective.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Standard ACLs match source addresses.
✗
The host 192.168.1.100 is exposed to denial-of-service attacks
Why it's wrong here
While possible, the immediate risk is the blanket permit rule.
Common exam traps
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
Standard ACLs match source addresses.
Extended ACLs can match source, destination, protocol and ports.
The first matching ACL entry is used.
There is usually an implicit deny at the end.
TExam Day Tips
→Check inbound versus outbound direction.
→Read the ACL from top to bottom.
→Look for a broader permit or deny above the intended line.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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.
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related CISA ACL questions on filtering logic and placement.
Governance and Management of IT — This question tests Governance and Management of IT — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: Unrestricted traffic is allowed after the specific deny — Option C is correct because the 'permit ip any any' at the end allows all traffic, bypassing earlier specific denials. Option A is not correct because the deny line only blocks other traffic, but the permit any any overrides it. Option B is not directly indicated. Option D is a risk but less direct than the rule order issue.
What should I do if I get this CISA question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related CISA ACL questions on filtering logic and placement.
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?
Standard ACLs match source addresses.
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