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 operations center (SOC) analyst is investigating an alert from the endpoint detection and response (EDR) system indicating that a process named "svchost.exe" spawned from a parent process "cmd.exe" on a user workstation. The user is a software developer who frequently uses command-line tools. The analyst checks the command line arguments: "cmd.exe /c powershell -EncodedCommand ...". The encoded command decodes to a script that downloads a payload from a remote server and executes it. The analyst also sees that the workstation has established an outbound connection to the same server on port 443. Which of the following is the BEST immediate action?
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
✓
Isolate the workstation from the network.
Isolating the workstation is the best immediate action because the EDR alert confirms active compromise: a malicious encoded PowerShell command executed via cmd.exe spawned svchost.exe (a process commonly abused for masquerading), and an outbound connection to the same C2 server on port 443 (HTTPS) indicates ongoing data exfiltration or further payload delivery. Network isolation stops all communication with the attacker while preserving forensic evidence on the endpoint, which is critical for containment in a SOC response.
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.
✓
Isolate the workstation from the network.
Why this is correct
Immediately contains the threat by preventing further communication and lateral movement.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Disable the user account.
Why it's wrong here
Does not stop the running process or connection.
✗
Kill the svchost.exe process.
Why it's wrong here
May not be sufficient if malware has dropped other components; also svchost is legitimate and killing it could cause issues.
✗
Block the remote server IP at the firewall.
Why it's wrong here
Helpful but may not stop the already-running payload; isolation is more comprehensive.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CompTIA often tests the misconception that blocking the remote IP or killing the process is sufficient, but the trap here is that the active outbound connection and running payload require immediate network containment to prevent data exfiltration and lateral movement, not just reactive blocking or process termination.
Detailed technical explanation
How to think about this question
The encoded PowerShell command is a common technique to bypass command-line logging and static detection; decoding it reveals a download cradle (e.g., using System.Net.WebClient) that fetches a second-stage payload over HTTPS (port 443). Svchost.exe is a critical Windows service host process, and adversaries often use it for masquerading by renaming their malware or performing process hollowing, making it difficult to kill without impacting system stability. In real-world incidents, isolating the workstation (e.g., via EDR network containment) is prioritized over IP blocking because C2 infrastructure is ephemeral and the immediate risk is the active beacon.
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 SOC analyst notices unusual lateral movement in the network at 2 AM. The IR playbook dictates: identify and contain (isolate the affected machine), then eradicate (remove the malware), then recover (restore from backup), then document. Skipping containment before eradication risks the attacker regaining access. Questions like this test the sequence and rationale of incident response phases.
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: Isolate the workstation from the network. — Isolating the workstation is the best immediate action because the EDR alert confirms active compromise: a malicious encoded PowerShell command executed via cmd.exe spawned svchost.exe (a process commonly abused for masquerading), and an outbound connection to the same C2 server on port 443 (HTTPS) indicates ongoing data exfiltration or further payload delivery. Network isolation stops all communication with the attacker while preserving forensic evidence on the endpoint, which is critical for containment in a SOC response.
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: "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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