The answer is to create custom exceptions for the specific signatures causing false positives for the legitimate application. This approach is correct because it directly addresses the problem of reducing IDS false positives for encrypted traffic through signature tuning, targeting only the known benign pattern without disabling broader detection. By suppressing alerts for a specific signature tied to the encrypted application, you preserve the IDS’s ability to catch actual threats in other encrypted streams, which is critical since encrypted payloads often evade simple pattern matching. On the ISC2 Certified in Cybersecurity CC exam, this tests your understanding of precision in tuning—a common trap is choosing to whitelist the entire host or disable the signature broadly, which would create security gaps. Remember the mnemonic “Specific Suppression, Secure Detection” to recall that the best tuning isolates the noise without sacrificing visibility.
ISC2 CC Security Operations Practice Question
This CC practice question tests your understanding of security operations. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
You are a security engineer responsible for the company's intrusion detection system (IDS). The IDS has been generating an excessive number of false positive alerts related to a legitimate application that uses encrypted traffic. The alerts are based on network signatures that match certain patterns in the encrypted payload. The volume of alerts is overwhelming the SOC team, and they are beginning to ignore IDS alerts altogether. You have the ability to modify IDS signatures and tune the system. Which of the following is the BEST approach to reduce false positives while maintaining security?
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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create custom exceptions for the specific signatures that are causing false positives for the legitimate application.
Option A is correct because creating custom exceptions for the specific signatures that trigger false positives allows you to suppress alerts for the legitimate application without disabling broader detection capabilities. This targeted approach preserves the IDS's ability to detect actual threats in encrypted traffic while reducing noise for the SOC team. It is the most precise tuning method, as it only excludes the known benign traffic pattern rather than broadly disabling signatures or whitelisting entire hosts.
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.
✓
Create custom exceptions for the specific signatures that are causing false positives for the legitimate application.
Why this is correct
This targeted approach reduces false positives while retaining overall detection capability.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Add the application's source IP addresses to a whitelist to suppress all alerts from that host.
Why it's wrong here
Whitelisting the IP could suppress alerts for real attacks originating from that host.
✗
Increase the threshold for alert generation so fewer alerts fire.
Why it's wrong here
Raising the threshold may suppress true positive alerts.
✗
Disable all signatures that trigger on encrypted traffic.
Why it's wrong here
This would eliminate all detection for encrypted threats, which is too broad.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose IP whitelisting (Option B) because it seems quick and easy, but Cisco tests the understanding that whitelisting entire hosts is overly broad and can hide malicious activity from the same source, whereas signature-specific exceptions are the correct, surgical tuning method.
Detailed technical explanation
How to think about this question
In practice, IDS signatures for encrypted traffic often rely on metadata such as TLS handshake parameters (e.g., JA3 fingerprints, certificate details, or SNI values) rather than payload content, since the payload is encrypted. Creating custom exceptions can involve adding a rule to skip signature matching for specific combinations of source IP, destination port, and protocol fields, or using a 'pass' action in Snort/Suricata rule syntax (e.g., 'pass tcp $HOME_NET any -> $EXTERNAL_NET 443 (msg:"Legitimate app bypass"; sid:1000001;)'). This approach maintains detection for other encrypted threats while eliminating the specific false positive pattern.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CC question in full detail.
Security Operations — This question tests Security Operations — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create custom exceptions for the specific signatures that are causing false positives for the legitimate application. — Option A is correct because creating custom exceptions for the specific signatures that trigger false positives allows you to suppress alerts for the legitimate application without disabling broader detection capabilities. This targeted approach preserves the IDS's ability to detect actual threats in encrypted traffic while reducing noise for the SOC team. It is the most precise tuning method, as it only excludes the known benign traffic pattern rather than broadly disabling signatures or whitelisting entire hosts.
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: "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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