- A
An inbound connection from a known malicious IP to the mail server
Why wrong: This indicates an attack attempt or initial compromise, not an established C2 channel from the internal host.
- B
A high volume of outbound traffic to an unusual destination IP on port 443
High volume outbound traffic to an unusual IP on 443 could be data exfiltration or C2 traffic masquerading as HTTPS.
- C
A single large file upload to a cloud storage service
Why wrong: This could be legitimate business use, not inherently indicative of C2.
- D
An internal host performing a DNS query for a known malicious domain
Why wrong: This is often a precursor to C2 but not necessarily successful communication; the DNS query may be blocked or unanswered.
- E
Regular beaconing activity to an external IP with consistent payload sizes
Beaconing with consistent intervals and payload sizes is a hallmark of C2 communication.
CS0-003 Security Operations Practice Question
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.
A security analyst is reviewing alerts from an IDS. Which TWO indicators are most likely to suggest a successful command and control (C2) communication? (Choose two.)
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 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
A high volume of outbound traffic to an unusual destination IP on port 443
B is correct because a high volume of outbound traffic to an unusual destination IP on port 443 (HTTPS) is a classic indicator of data exfiltration or C2 communication, as attackers often use encrypted channels to blend in with legitimate web traffic. The combination of high volume and an unusual destination IP suggests the host is sending data to an external server controlled by the attacker, which is a key sign of an active C2 session.
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.
- ✗
An inbound connection from a known malicious IP to the mail server
Why it's wrong here
This indicates an attack attempt or initial compromise, not an established C2 channel from the internal host.
- ✓
A high volume of outbound traffic to an unusual destination IP on port 443
Why this is correct
High volume outbound traffic to an unusual IP on 443 could be data exfiltration or C2 traffic masquerading as HTTPS.
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.
- ✗
A single large file upload to a cloud storage service
Why it's wrong here
This could be legitimate business use, not inherently indicative of C2.
- ✗
An internal host performing a DNS query for a known malicious domain
Why it's wrong here
This is often a precursor to C2 but not necessarily successful communication; the DNS query may be blocked or unanswered.
- ✓
Regular beaconing activity to an external IP with consistent payload sizes
Why this is correct
Beaconing with consistent intervals and payload sizes is a hallmark of C2 communication.
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.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the distinction between attempted and successful C2 communication, where candidates mistakenly choose indicators like DNS queries or inbound connections as proof of success, but only outbound beaconing or sustained data transfer on unusual ports confirms an established C2 channel.
Detailed technical explanation
How to think about this question
C2 communication often uses HTTP/HTTPS on port 443 to evade detection, as many firewalls allow outbound HTTPS traffic. Beaconing activity (option E) is a hallmark of C2, where the compromised host sends periodic, small packets with consistent payload sizes to maintain persistence and receive commands; tools like Cobalt Strike or Metasploit use such patterns. Under the hood, the IDS may detect this by analyzing packet timing and payload entropy, distinguishing it from human web browsing which has variable intervals and payload sizes.
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 developer is choosing between AES-256 (symmetric) and RSA-2048 (asymmetric) for encrypting a large file that will be sent to a partner. Symmetric encryption is fast but requires key exchange; asymmetric is slower but solves the key distribution problem. A hybrid approach — encrypt the file with AES, encrypt the AES key with RSA — is standard. Questions like this test whether you understand when each approach 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.
- →
Security Operations — study guide chapter
Learn the concepts, then practise the questions
- →
Security Operations practice questions
Targeted practice on this topic area only
- →
All CS0-003 questions
503 questions across all exam domains
- →
CompTIA CySA+ CS0-003 study guide
Full concept coverage aligned to exam objectives
- →
CS0-003 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related CS0-003 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Security Operations practice questions
Practise CS0-003 questions linked to Security Operations.
Vulnerability Management practice questions
Practise CS0-003 questions linked to Vulnerability Management.
Incident Response and Management practice questions
Practise CS0-003 questions linked to Incident Response and Management.
Reporting and Communication practice questions
Practise CS0-003 questions linked to Reporting and Communication.
CompTIA A+ hardware practice questions
Practise CS0-003 questions linked to CompTIA A+ hardware.
CompTIA A+ mobile devices practice questions
Practise CS0-003 questions linked to CompTIA A+ mobile devices.
CompTIA A+ networking practice questions
Practise CS0-003 questions linked to CompTIA A+ networking.
CompTIA A+ operating systems practice questions
Practise CS0-003 questions linked to CompTIA A+ operating systems.
CompTIA A+ security practice questions
Practise CS0-003 questions linked to CompTIA A+ security.
CompTIA A+ software troubleshooting questions
Practise CS0-003 questions linked to CompTIA A+ software troubleshooting questions.
CompTIA A+ operational procedures questions
Practise CS0-003 questions linked to CompTIA A+ operational procedures questions.
Practice this exam
Start a free CS0-003 practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this CS0-003 question test?
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: A high volume of outbound traffic to an unusual destination IP on port 443 — B is correct because a high volume of outbound traffic to an unusual destination IP on port 443 (HTTPS) is a classic indicator of data exfiltration or C2 communication, as attackers often use encrypted channels to blend in with legitimate web traffic. The combination of high volume and an unusual destination IP suggests the host is sending data to an external server controlled by the attacker, which is a key sign of an active C2 session.
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.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 25, 2026
This CS0-003 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CS0-003 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.