This CS0-003 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.
Which THREE of the following are common indicators of a data exfiltration attempt? (Choose three.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Outbound connections to IP addresses associated with known C2 servers
Option A is correct because outbound connections to IP addresses associated with known command-and-control (C2) servers are a classic indicator of data exfiltration. Once an attacker establishes a C2 channel, they can use it to tunnel stolen data out of the network. Security tools like firewalls and threat intelligence feeds flag these connections based on known malicious IP addresses or domains.
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.
✓
Outbound connections to IP addresses associated with known C2 servers
Why this is correct
Direct indication of malicious activity.
Related concept
Read the scenario before looking for a memorised answer.
✓
DNS queries with high entropy subdomains
Why this is correct
Common DNS tunneling technique for data exfiltration.
Related concept
Read the scenario before looking for a memorised answer.
✗
Increased use of encrypted communication protocols
Why it's wrong here
Encryption is normal; could be legitimate.
✓
Unusually large outbound data transfers during off-hours
Why this is correct
Exfiltration often uses non-business hours.
Related concept
Read the scenario before looking for a memorised answer.
✗
Multiple failed login attempts from a single source
Why it's wrong here
Indicates brute force, not exfiltration.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA often tests the distinction between indicators of exfiltration (data leaving) versus indicators of initial access or lateral movement, so candidates may confuse failed logins (Option E) with exfiltration when it actually points to a different phase of the attack chain.
Detailed technical explanation
How to think about this question
Data exfiltration often leverages DNS tunneling, where attackers encode stolen data in DNS queries to high-entropy subdomains (e.g., 'a3f8b2c1.malicious.com') to bypass network filters. Similarly, unusually large outbound transfers during off-hours may be detected by network traffic analysis tools like NetFlow or Zeek, which can flag deviations from baseline traffic patterns. Real-world attacks, such as those using the 'MegaCortex' ransomware, have used these techniques to exfiltrate data before encryption.
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 CS0-003 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: Outbound connections to IP addresses associated with known C2 servers — Option A is correct because outbound connections to IP addresses associated with known command-and-control (C2) servers are a classic indicator of data exfiltration. Once an attacker establishes a C2 channel, they can use it to tunnel stolen data out of the network. Security tools like firewalls and threat intelligence feeds flag these connections based on known malicious IP addresses or domains.
What should I do if I get this CS0-003 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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