Question 71 of 509
Information System Auditing ProcessmediumMultiple ChoiceObjective-mapped

Quick Answer

The answer is that the host may be attempting to bypass security controls by using different protocols. This pattern of denied SSH attempts followed by allowed HTTPS connections is a classic example of protocol hopping, where an internal host first probes for an open SSH service on one server and, when blocked, switches to a permitted protocol like HTTPS to communicate with a different server. On the CISA exam, this scenario tests your ability to interpret firewall log analysis as part of evaluating network security controls and detecting evasion techniques. A common trap is to focus solely on the denied SSH attempts without recognizing the significance of the subsequent successful HTTPS connection, which reveals adaptive behavior. Remember the memory tip: “Denied then allowed? Protocol hopping is clouded.”

CISA Information System Auditing Process Practice Question

This CISA practice question tests your understanding of information system auditing process. 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.

```
# Audit log extract from firewall 'FW-Primary'
2024-03-15 14:22:33 | rule_id=101 | action=deny | src=10.0.1.50 | dst=172.16.0.1 | port=22 | status=alert
2024-03-15 14:22:34 | rule_id=101 | action=deny | src=10.0.1.50 | dst=172.16.0.1 | port=22 | status=alert
2024-03-15 14:22:35 | rule_id=101 | action=deny | src=10.0.1.50 | dst=172.16.0.1 | port=22 | status=alert
2024-03-15 14:23:01 | rule_id=105 | action=permit | src=10.0.1.50 | dst=172.16.0.5 | port=443 | status=alert
2024-03-15 14:23:02 | rule_id=105 | action=permit | src=10.0.1.50 | dst=172.16.0.5 | port=443 | status=alert
```

Refer to the exhibit. An IS auditor is reviewing firewall logs and notices repeated denied SSH attempts from an internal host (10.0.1.50) to a server (172.16.0.1). After the denied attempts, the host initiates permitted HTTPS connections to another server (172.16.0.5). Which of the following is the BEST interpretation of this pattern?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "best"

    Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.

Question 1mediummultiple choice
Read the full NAT/PAT explanation →

Exhibit

Refer to the exhibit.

```
# Audit log extract from firewall 'FW-Primary'
2024-03-15 14:22:33 | rule_id=101 | action=deny | src=10.0.1.50 | dst=172.16.0.1 | port=22 | status=alert
2024-03-15 14:22:34 | rule_id=101 | action=deny | src=10.0.1.50 | dst=172.16.0.1 | port=22 | status=alert
2024-03-15 14:22:35 | rule_id=101 | action=deny | src=10.0.1.50 | dst=172.16.0.1 | port=22 | status=alert
2024-03-15 14:23:01 | rule_id=105 | action=permit | src=10.0.1.50 | dst=172.16.0.5 | port=443 | status=alert
2024-03-15 14:23:02 | rule_id=105 | action=permit | src=10.0.1.50 | dst=172.16.0.5 | port=443 | status=alert
```

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 host may be attempting to bypass security controls by using different protocols

The pattern of denied SSH attempts followed by successful HTTPS connections suggests the internal host is probing for an open SSH service and, when blocked, switches to an allowed protocol (HTTPS) to communicate with a different server. This behavior indicates an attempt to bypass security controls by leveraging a permitted protocol after initial reconnaissance or direct access attempts fail. The firewall logs show the host adapts its method, which is a classic indicator of protocol hopping or tunneling attempts.

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 host may be attempting to bypass security controls by using different protocols

    Why this is correct

    The pattern indicates probing blocked service then using permitted service, possibly to evade detection.

    Clue confirmation

    The clue word "best" in the question point toward this answer.

    Related concept

    Read the scenario before looking for a memorised answer.

  • The firewall rule 101 is misconfigured and blocking legitimate traffic

    Why it's wrong here

    SSH to that destination may be legitimate to block; no evidence of misconfiguration.

  • The host is performing reconnaissance and has mapped allowed services

    Why it's wrong here

    The denied attempts show blocked scanning, but the HTTPS is allowed; not necessarily mapping.

  • The host successfully accessed server 172.16.0.1 via SSH

    Why it's wrong here

    The logs show denied actions, not successful access.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates may focus on the reconnaissance aspect (option C) and overlook the deliberate protocol switch, which is the key indicator of an attempt to bypass security controls rather than just map services.

Trap categories for this question

  • Command / output trap

    The denied attempts show blocked scanning, but the HTTPS is allowed; not necessarily mapping.

Detailed technical explanation

How to think about this question

This scenario often involves an attacker using SSH tunneling over HTTPS (e.g., via SSH over port 443 or using tools like stunnel) to exfiltrate data or maintain command and control. The firewall rule 101 likely blocks SSH (TCP port 22) to 172.16.0.1, but HTTPS (TCP port 443) to 172.16.0.5 is permitted, which could allow the host to encapsulate SSH traffic within TLS, effectively bypassing the firewall's layer-4 inspection. Real-world examples include compromised internal hosts using SSH over HTTPS to evade detection in environments with strict egress filtering.

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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.

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.

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FAQ

Questions learners often ask

What does this CISA question test?

Information System Auditing Process — This question tests Information System Auditing Process — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The host may be attempting to bypass security controls by using different protocols — The pattern of denied SSH attempts followed by successful HTTPS connections suggests the internal host is probing for an open SSH service and, when blocked, switches to an allowed protocol (HTTPS) to communicate with a different server. This behavior indicates an attempt to bypass security controls by leveraging a permitted protocol after initial reconnaissance or direct access attempts fail. The firewall logs show the host adapts its method, which is a classic indicator of protocol hopping or tunneling attempts.

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: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 25, 2026

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