CHFI Mobile and Malware Forensics Practice Question
In Android forensics, which of the following acquisition methods provides the most complete and forensically sound image of the device's internal storage?
⚠ Common exam trap
EC-Council often tests the misconception that logical extraction via ADB is sufficient for a complete forensic image, but candidates must recognize that only physical methods (JTAG/chip-off) capture the entire raw storage, including deleted and hidden data.
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
✓
Physical extraction using a JTAG or chip-off technique
Physical extraction using a JTAG or chip-off technique provides the most complete and forensically sound image because it accesses the raw NAND flash memory at the hardware level, bypassing the operating system and any software-based restrictions. This method captures deleted data, unallocated space, and the entire file system structure, including areas not accessible via logical or file system extractions, ensuring a bit-for-bit copy of the internal storage.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Manual extraction through the user interface
Why it's wrong here
Manual extraction through the user interface relies on a human operator navigating the device's touchscreen to view and manually copy data, such as screenshots, contacts, or messages. This method is inherently unsound for forensic purposes because it alters the device state through user interaction, is limited to data visible to the operator, and cannot access hidden, deleted, or system-protected artifacts. Moreover, the captured data lacks cryptographic hash verification and a proper chain of custody, making it inadmissible in court as a reliable forensic copy.
- ✗
Logical extraction via ADB
Why it's wrong here
Logical extraction via ADB (Android Debug Bridge) sends high-level commands to the Android system to enumerate and copy files that are accessible through the standard file-system APIs, typically under /sdcard, /data/media, and app-specific data directories if permissions allow. While this method is more automated and forensically sound than manual tapping, it operates at the logical layer and only retrieves active, allocated files; it cannot recover deleted files, remnants in unallocated space, or data hidden in slack space. Because logical extractions rely on the live operating system to interpret the file system, they also modify file access times and may fail to capture complete application databases that are locked or protected by Android’s sandboxing.
- ✗
File system extraction
Why it's wrong here
File system extraction in Android forensics obtains a raw image of the file system structures, including free blocks, but only at the file-system level rather than the full physical flash chip. This method is typically performed on a rooted device or via an exploit that provides low-level access, allowing the examiner to capture allocated and unallocated blocks within a partition, along with file metadata and deleted file entries that have not yet been overwritten. However, it does not recover data from other partitions outside the selected file system, nor does it include the bootloader, radio firmware, or device configuration areas; moreover, it requires kernel-level cooperation and can be incomplete if the flash translation layer or wear leveling has moved data physically.
- ✓
Physical extraction using a JTAG or chip-off technique
Why this is correct
Physical extraction using a JTAG or chip-off technique is the most comprehensive acquisition method because it reads the raw flash memory chips directly, bypassing the Android operating system and its file system driver. JTAG (Joint Test Action Group) connects to the device's test access port to command the CPU to dump the flash contents, while chip-off involves physically desoldering the NAND/eMMC chip and reading it with a dedicated programmer; both yield a complete bit-for-bit image of the entire flash memory, including deleted files, unallocated space, hidden partitions, and data remnants that software-based methods cannot access. This approach is particularly valuable when the device is damaged, locked, or otherwise unresponsive, though it is invasive, may require breaking the device, and demands deep knowledge of the specific chip datasheet and interface protocols.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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