The answer is that the suspect drive was connected before the write-blocker was powered on. This is the most likely cause because write-blockers function by intercepting and filtering ATA or SCSI commands at the hardware level before the operating system enumerates the drive; if the drive is physically connected first, the OS may have already recognized it as a writable device and cached write attributes, effectively bypassing the blocker’s protection. On the Computer Hacking Forensic Investigator CHFI exam, this scenario tests your understanding of forensic hardware acquisition procedures and the critical power-on sequence—a common trap is assuming the blocker alone guarantees protection regardless of connection order. To remember, think of the mnemonic “Power before Plug”: always power on the write-blocker before connecting the suspect drive to ensure the OS never sees the drive as writable.
CHFI Computer Forensics Lab Practice Question
This CHFI practice question tests your understanding of computer forensics lab. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 forensic analyst is troubleshooting a write-blocker that is not working correctly. The analyst connected the write-blocker between the suspect drive and the forensic workstation, but the workstation still shows the drive as writable. What is the most likely cause?
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 the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The suspect drive was connected before the write-blocker was powered on
When a write-blocker is powered on after the suspect drive is already connected, the drive may have already been enumerated by the operating system as a writable device. Write-blockers rely on intercepting and filtering ATA/SCSI commands at the hardware level before the OS sees the drive; if the drive is connected first, the OS may have already sent write commands or cached write attributes, bypassing the blocker's protection. This is why the proper sequence is to power on the write-blocker first, then connect the suspect drive.
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.
✓
The suspect drive was connected before the write-blocker was powered on
Why this is correct
Connecting the drive before powering the write-blocker can bypass the write-block.
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.
✗
The write-blocker does not have external power
Why it's wrong here
Most write-blockers are powered via USB or external adapter.
✗
The suspect drive uses SATA but the write-blocker is USB-only
Why it's wrong here
If the write-blocker supports SATA, this is not an issue.
✗
The write-blocker is connected to the suspect drive's output port
Why it's wrong here
The write-blocker should be between the workstation and the drive.
Common exam traps
Common exam trap: answer the scenario, not the keyword
EC-Council often tests the power-on sequence as a subtle but critical procedural step, knowing that candidates may focus on hardware compatibility or cabling errors instead of the order of operations.
Detailed technical explanation
How to think about this question
Write-blockers implement hardware-level command filtering by sitting on the SATA or USB bus and intercepting ATA commands such as WRITE DMA or WRITE SECTORS, returning a command aborted status instead of executing them. The USB Mass Storage Bulk-Only Transport (BOT) protocol does not inherently enforce read-only access; the blocker must actively modify the device descriptor to report the drive as read-only or filter commands at the transport layer. In forensic practice, the 'power-on sequence' is critical because USB and SATA hot-plug events trigger OS enumeration; if the drive is present before the blocker is active, the OS may cache write capabilities that persist even after the blocker is powered.
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 practitioner preparing for the CHFI exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CHFI question in full detail.
Computer Forensics Lab — This question tests Computer Forensics Lab — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The suspect drive was connected before the write-blocker was powered on — When a write-blocker is powered on after the suspect drive is already connected, the drive may have already been enumerated by the operating system as a writable device. Write-blockers rely on intercepting and filtering ATA/SCSI commands at the hardware level before the OS sees the drive; if the drive is connected first, the OS may have already sent write commands or cached write attributes, bypassing the blocker's protection. This is why the proper sequence is to power on the write-blocker first, then connect the suspect drive.
What should I do if I get this CHFI 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.
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Question Discussion
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