CAS-004 Security Operations Practice Question
A penetration tester is conducting a test against a web application. The client has defined rules of engagement that prohibit any denial of service attacks. The tester discovers an endpoint that is vulnerable to command injection. Which THREE of the following actions should the tester take to validate the vulnerability while staying within scope? (Choose THREE.)
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
✓
Use the echo command to write a file on the server
To validate command injection without causing damage, the tester should use non-destructive commands like ping, echo, and whoami. Deleting files or performing DoS would violate rules of engagement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use the echo command to write a file on the server
Why this is correct
Writing a harmless file can prove execution without damage.
- ✓
Run a whoami command to confirm the user context
Why this is correct
This is non-destructive and provides useful information.
- ✗
Delete a random system file to observe impact
Why it's wrong here
This is destructive and likely violates rules of engagement.
- ✗
Flood the endpoint with multiple requests to test resilience
Why it's wrong here
This would constitute a DoS attack, which is prohibited.
- ✓
Execute a ping command to a controlled server to verify code execution
Why this is correct
This is a safe way to confirm command injection.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CAS-005 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 CAS-005 exam.