Quick Answer
The correct answer is to prevent any writes to the original evidence drive. A hardware write blocker physically sits between the suspect drive and the forensic workstation, intercepting and blocking all write commands from the host operating system at the hardware level, so the source drive remains completely unaltered. This is the cornerstone of maintaining digital evidence integrity, because any modification—even a single bit—can render the evidence inadmissible in court. On the CHFI exam, this concept tests your understanding of forensic acquisition best practices; a common trap is confusing a hardware blocker with a software blocker, which can be bypassed or fail if the OS doesn’t recognize the drive. Remember the mnemonic “Block the Write, Keep the Light”—the blocker stops writes while the forensic tool still reads the evidence, preserving its pristine state for analysis.
This CHFI practice question tests your understanding of evidence acquisition and duplication. 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.
Which of the following is the primary purpose of using a hardware write blocker during disk acquisition?
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.
To decrypt the drive during acquisition
Why wrong: Write blockers do not perform decryption.
To prevent any writes to the original evidence drive
This ensures the integrity of the evidence.
To compress the acquired image
Why wrong: Compression is done by software, not hardware write blockers.
To increase the speed of the acquisition
Why wrong: Write blockers do not increase speed.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
To prevent any writes to the original evidence drive
A hardware write blocker is a device placed between the suspect drive and the forensic workstation that intercepts and blocks any write commands from the host operating system, ensuring that the original evidence drive remains unaltered. This is critical for maintaining the integrity of digital evidence, as any modification to the source drive could render it inadmissible in court. The primary purpose is therefore to prevent any writes to the original evidence drive, preserving its exact state for forensic analysis.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
To decrypt the drive during acquisition
Why it's wrong here
Write blockers do not perform decryption.
To prevent any writes to the original evidence drive
Why this is correct
This ensures the integrity of the evidence.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
To compress the acquired image
Why it's wrong here
Compression is done by software, not hardware write blockers.
To increase the speed of the acquisition
Why it's wrong here
Write blockers do not increase speed.
Common exam traps
EC-Council often tests the misconception that a write blocker performs active functions like decryption or compression, when in reality it is a passive hardware filter that only enforces read-only access at the bus level.
Detailed technical explanation
Under the hood, a hardware write blocker operates at the ATA/SCSI command level, intercepting commands such as WRITE DMA or WRITE SECTORS and returning a command aborted status, while allowing READ commands to pass through. In real-world scenarios, a subtle behavior is that some write blockers also filter out IDENTIFY DEVICE commands to prevent the host from sending a security erase or other destructive ATA commands, which could otherwise modify the drive's firmware or security settings. This is especially important when dealing with self-encrypting drives (SEDs) where a write blocker must also block cryptographic erase commands.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Evidence Acquisition and Duplication — This question tests Evidence Acquisition and Duplication — Read the scenario before looking for a memorised answer..
The correct answer is: To prevent any writes to the original evidence drive — A hardware write blocker is a device placed between the suspect drive and the forensic workstation that intercepts and blocks any write commands from the host operating system, ensuring that the original evidence drive remains unaltered. This is critical for maintaining the integrity of digital evidence, as any modification to the source drive could render it inadmissible in court. The primary purpose is therefore to prevent any writes to the original evidence drive, preserving its exact state for forensic analysis.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
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 →
Same concept, more angles
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which TWO of the following are valid reasons for using a hardware write blocker during disk acquisition? (Choose two.)
easyWhy C: A hardware write blocker is a device that sits between the source drive and the forensic workstation, intercepting and blocking any write commands from the host operating system. This ensures that the source drive is connected in a read-only state, preventing any accidental modifications to the evidence during acquisition. Option C correctly identifies this core function of preserving the integrity of the source drive.
Last reviewed: Jun 30, 2026
This CHFI practice question is part of Courseiva's free EC-Council 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 CHFI exam.
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