Introduction: The Critical Role of Android RAM Forensics

In the ever-evolving landscape of mobile malware, understanding the execution environment and transient data is paramount for effective analysis. Android RAM dumping, also known as memory acquisition, is a fundamental technique in mobile forensics that allows investigators to capture the volatile memory contents of an Android device. This memory often holds critical artifacts like running processes, open network connections, decryption keys, injected code, and other runtime data that persistent storage might not reveal, especially after a device has been powered off or tampered with. This guide provides a detailed, step-by-step approach for acquiring RAM from Android devices, tailored for security professionals and malware analysts.

Prerequisites and Tools

Before embarking on the memory acquisition process, ensure you have the following:

• Rooted Android Device: Most RAM dumping methods require root access to interact with low-level device files.
• ADB (Android Debug Bridge): Essential for interacting with the device from your workstation.
• Workstation with Linux/macOS: Recommended for forensic tools; Windows with WSL also works.
• Sufficient Storage: The RAM dump size can range from hundreds of megabytes to several gigabytes, depending on the device’s RAM capacity.
• Memory Forensics Framework: Tools like Volatility or Rekall for post-acquisition analysis.

Understanding Android Memory & Acquisition Targets

Android’s kernel, like Linux, exposes memory-related pseudo-files and devices. The primary targets for RAM dumping are:

• /proc/kcore: A pseudo-file that represents the kernel’s view of the physical memory. It’s often the most accessible target for dumping the kernel and mapped user-space memory on a live, rooted system.
• /dev/mem: Represents the physical memory of the system. Accessing this usually requires specific kernel modules or higher privileges and might be restricted on many Android kernels.

For most practical live forensic scenarios on a rooted device, /proc/kcore is the preferred method due to its relative accessibility and comprehensive snapshot capability of the kernel and associated user-space memory mappings.

Method 1: Live RAM Dumping via ADB on a Rooted Device

This method utilizes the dd (data duplicator) utility available on most Linux-based systems, including Android, to read directly from /proc/kcore.

Step 1: Enable ADB and Root Access

Ensure your Android device has Developer Options enabled, USB debugging is active, and the device is properly rooted (e.g., Magisk). Connect it to your workstation via USB.

adb devices

You should see your device listed. If not, check drivers and USB debugging settings.

Step 2: Obtain Root Shell and Set Permissions

First, restart ADB in root mode. Then, switch to a root shell on the device.

adb rootadb shellsu

Confirm you have root access (the prompt should change from $ to #). Navigate to a writable location on the device, such as /sdcard/ or /data/local/tmp/.

Step 3: Dump RAM using dd

Use the dd command to copy the contents of /proc/kcore to a file on the device’s internal storage. This process can take several minutes to an hour, depending on the device’s RAM size and I/O speed.

dd if=/proc/kcore of=/sdcard/android_ram_dump.mem bs=1M

Explanation of parameters:

• if=/proc/kcore: Specifies the input file (the kernel’s memory representation).
• of=/sdcard/android_ram_dump.mem: Specifies the output file path on the device. Ensure there’s enough space.
• bs=1M: Sets the block size to 1 megabyte, which can significantly speed up the transfer.

Note: While /proc/kcore is good for kernel and mapped user-space memory, a true full physical RAM dump can be challenging without specialized hardware or a custom kernel module that exposes /dev/mem more permissively or provides an alternative mechanism.

Step 4: Pull the RAM Dump to Your Workstation

Once the dd command completes on the device, pull the acquired memory dump file to your analysis workstation.

adb pull /sdcard/android_ram_dump.mem .

This command pulls the file to your current directory on the workstation.

Method 2: RAM Dumping via Custom Recovery (TWRP)

Using a custom recovery environment like TWRP (Team Win Recovery Project) can offer a more isolated environment for dumping, as the main Android OS is not running, minimizing interference from active processes or malware.

Step 1: Install TWRP and Boot into Recovery

Ensure your device has TWRP installed and boot into the recovery mode.

Step 2: Connect via ADB

With the device in TWRP, connect it to your workstation. TWRP typically starts its own ADB daemon, allowing you to access a shell.

adb devices

You should see your device listed, usually with a status like