The correct answer is that this script conducts a TCP SYN scan to identify hosts with port 22 open. The command uses hping3 with the -S flag to send a SYN packet to each IP in the subnet, and then checks for a SYN-ACK response (flags=SA), which confirms the port is open and listening—this is the defining behavior of a half-open scan, as no full TCP connection is completed. On the CompTIA PenTest+ PT0-002 exam, this question tests your ability to interpret a real-world bash script for pentest reconnaissance, specifically distinguishing a SYN scan from a full connect scan or a ping sweep. A common trap is confusing the -S flag with a stealth scan versus a connect() scan; remember that SYN scans never complete the handshake, so they are faster and less likely to be logged. Memory tip: “SA” means “SYN-Ack,” so if you see flags=SA, the port is saying “Yes, I’m open.”
PT0-002 Tools and Code Analysis Practice Question
This PT0-002 practice question tests your understanding of tools and code analysis. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 penetration tester is analyzing a Bash script that performs network scanning. The script contains the following command: 'for ip in $(seq 1 254); do hping3 -S -p 22 -c 1 $TARGET_SUBNET.$ip 2>/dev/null | grep -q "flags=SA" && echo "$TARGET_SUBNET.$ip: open"; done'. What is the primary purpose of this script?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "primary"
Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Conduct a TCP SYN scan to identify hosts with port 22 open
The script uses hping3 with the -S flag (SYN) and -p 22 (port 22) to send TCP SYN packets to each IP in the target subnet. The grep -q 'flags=SA' checks for a SYN-ACK response, which indicates the port is open and listening. This is the classic behavior of a TCP SYN scan (half-open scan) to identify hosts with port 22 open.
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.
✓
Conduct a TCP SYN scan to identify hosts with port 22 open
Why this is correct
The script sends SYN packets to port 22 and looks for SYN-ACK responses, which is the definition of a TCP SYN scan.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Perform a vulnerability assessment against SSH services
Why it's wrong here
A vulnerability assessment would involve sending specific probes or payloads; this script only checks if the port is open.
✗
Execute an ICMP ping sweep to discover live hosts
Why it's wrong here
ICMP ping sweeps use ICMP echo requests, not TCP packets. This script uses TCP SYN to port 22.
✗
Complete a full TCP three-way handshake and log successful connections
Why it's wrong here
The script only sends SYN and waits for SYN-ACK; it does not send the final ACK, so it is a half-open scan, not a full connection.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse a TCP SYN scan on a specific port with a general ICMP ping sweep, or assume that scanning port 22 automatically implies an SSH vulnerability assessment, when in fact the script only performs port discovery, not vulnerability testing.
Detailed technical explanation
How to think about this question
The hping3 -S flag sends a TCP SYN packet, and the -c 1 sends only one packet per IP. The 2>/dev/null suppresses error output (e.g., unreachable hosts), and grep -q 'flags=SA' matches only responses with both SYN and ACK flags set, which is the standard TCP three-way handshake response for an open port. A closed port would respond with RST (flags=RA), which would not match, and a filtered port would drop the packet or respond with ICMP unreachable, which is also suppressed.
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 team runs a vulnerability scan on a web application and discovers an unpatched SQL injection flaw. The team prioritises remediation by CVSS score — critical flaws are patched within 24 hours, high within 7 days. Questions like this test whether you understand vulnerability management processes, scanning tools, and remediation prioritisation.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this PT0-002 question in full detail.
Tools and Code Analysis — This question tests Tools and Code Analysis — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Conduct a TCP SYN scan to identify hosts with port 22 open — The script uses hping3 with the -S flag (SYN) and -p 22 (port 22) to send TCP SYN packets to each IP in the target subnet. The grep -q 'flags=SA' checks for a SYN-ACK response, which indicates the port is open and listening. This is the classic behavior of a TCP SYN scan (half-open scan) to identify hosts with port 22 open.
What should I do if I get this PT0-002 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: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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