Quick Answer
The answer is the `adb shell dd if=/dev/block/mmcblk0 of=/sdcard/physical.img` command, because it leverages the Linux `dd` utility to perform a bit-for-bit copy of the raw block device representing the device’s internal flash memory. This method captures a full physical image, including deleted data and unallocated space, which is essential for deep forensic analysis under the Computer Hacking Forensic Investigator (CHFI) framework. On the CHFI exam, this question tests your understanding of Android physical image extraction over USB via ADB, often contrasting it with logical acquisition methods like `adb backup` or `content://` providers. A common trap is confusing the block device path—remember that `mmcblk0` typically refers to the main internal storage, not an external SD card. For a quick memory tip, think “dd does a dead-on duplicate of the disk device” to recall that `dd` requires the exact block device path and an output destination, which you then pull using `adb pull`.
This CHFI practice question tests your understanding of mobile and malware forensics. 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.
In Android forensics, which command is used to extract a full physical image of a device's flash memory over USB using the Android Debug Bridge (ADB)?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "which command"
Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
adb pull /data data.img
Why wrong: adb pull copies individual files/directories, not a raw image of a partition.
adb shell dd if=/dev/block/mmcblk0 of=/sdcard/physical.img
dd copies the raw block device to a file, creating a physical image.
adb backup -f backup.ab
Why wrong: adb backup creates a logical backup, not a physical image.
adb install physical.img
Why wrong: adb install is for installing APK files, not for imaging.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
adb shell dd if=/dev/block/mmcblk0 of=/sdcard/physical.img
Option B is correct because the `adb shell dd if=/dev/block/mmcblk0 of=/sdcard/physical.img` command uses the `dd` utility to perform a bit-for-bit copy of the raw block device representing the internal flash memory (mmcblk0) to a file on the device's SD card, which can then be pulled via ADB. This method captures a full physical image, including deleted data and unallocated space, which is essential for deep 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.
adb pull /data data.img
Why it's wrong here
adb pull copies individual files/directories, not a raw image of a partition.
adb shell dd if=/dev/block/mmcblk0 of=/sdcard/physical.img
Why this is correct
dd copies the raw block device to a file, creating a physical image.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
adb backup -f backup.ab
Why it's wrong here
adb backup creates a logical backup, not a physical image.
adb install physical.img
Why it's wrong here
adb install is for installing APK files, not for imaging.
Common exam traps
Cisco often tests the distinction between logical acquisition (adb pull) and physical acquisition (adb shell dd), so the trap here is that candidates confuse the simple file copy command (adb pull) with the raw block-level imaging command (adb shell dd), assuming any command with 'pull' or 'backup' can produce a forensic image.
Detailed technical explanation
The `dd` command reads from the block device `/dev/block/mmcblk0`, which is the primary eMMC storage chip, and writes to a file; the resulting image is a raw binary dump that can be analyzed with tools like FTK Imager or Autopsy. In practice, the device must be rooted or have an unlocked bootloader to access the block device, and the image may need to be compressed or split due to size limits on the /sdcard partition. A subtle behavior is that `dd` does not skip bad blocks by default, so forensic examiners often add `conv=noerror,sync` to handle read errors without aborting.
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.
Mobile and Malware Forensics — study guide chapter
Learn the concepts, then practise the questions
Mobile and Malware Forensics practice questions
Targeted practice on this topic area only
All CHFI questions
1,000 questions across all exam domains
Computer Hacking Forensic Investigator CHFI study guide
Full concept coverage aligned to exam objectives
CHFI practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise CHFI questions linked to Computer Forensics Investigation Process.
Practise CHFI questions linked to Computer Forensics Fundamentals and Process.
Practise CHFI questions linked to Storage Forensics and File System Analysis.
Practise CHFI questions linked to Incident Response and First Responder Skills.
Practise CHFI questions linked to Computer Forensics Lab.
Practise CHFI questions linked to Evidence Acquisition and Duplication.
Practise CHFI questions linked to OS and Network Forensics.
Practise CHFI questions linked to OS and File System Forensics.
Practise CHFI questions linked to Application, Email and Cloud Forensics.
Practise CHFI questions linked to Mobile and Malware Forensics.
Practise CHFI questions linked to Network and Cloud Forensics.
Practise CHFI questions linked to Database and Application Forensics.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Mobile and Malware Forensics — This question tests Mobile and Malware Forensics — Read the scenario before looking for a memorised answer..
The correct answer is: adb shell dd if=/dev/block/mmcblk0 of=/sdcard/physical.img — Option B is correct because the `adb shell dd if=/dev/block/mmcblk0 of=/sdcard/physical.img` command uses the `dd` utility to perform a bit-for-bit copy of the raw block device representing the internal flash memory (mmcblk0) to a file on the device's SD card, which can then be pulled via ADB. This method captures a full physical image, including deleted data and unallocated space, which is essential for deep 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: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
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 →
Last reviewed: Jun 24, 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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.