Introduction: The Rise of Android Automotive OS in Modern Vehicles

Android Automotive OS (AAOS) represents a significant shift in the automotive industry, moving beyond simple infotainment systems to become the full operating system for a vehicle’s head unit. Unlike Android Auto, which projects phone content to the car display, AAOS runs natively on vehicle hardware, integrating deeply with car systems and offering a rich ecosystem of Google services and third-party applications. This deep integration means AAOS-powered vehicles accumulate vast amounts of data—from navigation history and user preferences to vehicle diagnostics and communication logs. For forensic investigators, this presents a new frontier, requiring specialized knowledge and techniques to uncover hidden artifacts critical for accident reconstruction, criminal investigations, or intellectual property disputes.

This article delves into the methodologies for reverse engineering AAOS, identifying key data sources, and employing forensic tools to extract and analyze information embedded within these complex systems.

Understanding the Android Automotive OS Architecture

AAOS is built upon the standard Android Open Source Project (AOSP) but includes specific customizations for the automotive domain. Key architectural layers include:

• Vehicle Hardware Abstraction Layer (VHAL): This crucial layer acts as the interface between Android and the vehicle’s hardware, such as the CAN bus, sensors (speed, RPM, fuel level), and actuators. It allows Android applications to interact with vehicle-specific properties.
• Car Service: A central component in AAOS, the Car Service manages all vehicle-related services (audio, power, sensors, networking, etc.) and provides APIs for applications to access VHAL properties.
• Android Framework and Applications: Standard Android services, libraries, and applications (e.g., Google Maps, Spotify, Google Assistant) run on top of the Car Service, often customized for the automotive environment.

Key Components Relevant to Forensics:

• User Profiles: AAOS supports multiple user profiles, each potentially storing unique settings, accounts, and application data.
• Persistent Storage: Typically eMMC or UFS flash memory, containing the OS, application data, and user data.
• System Logs: Android’s `logcat` provides extensive logging, complemented by kernel logs (`dmesg`) and specific vehicle service logs.
• Application Databases: Many apps, especially navigation and media, store user-specific data in SQLite databases.

Accessing the AAOS System for Forensic Analysis

Accessing the target system is the foundational step in any forensic investigation. For AAOS, methods vary depending on the vehicle’s configuration and the level of physical access available.

1. ADB Access (If Available)

Android Debug Bridge (ADB) is the primary command-line tool for communicating with Android devices. If ADB debugging is enabled on the AAOS head unit (often found in developer options, or by specific OEM configurations), it provides a powerful remote interface.

# Check for connected devicesadb devices# Connect to the device via TCP/IP (if enabled over Wi-Fi)adb connect <IP_ADDRESS>:5555# Initiate a shell sessionadb shell# List installed packages and their pathsadb shell pm list packages -f

Gaining root access via ADB might be necessary for full filesystem exploration, but it’s often disabled or requires exploiting vulnerabilities specific to the OEM’s implementation.

2. Physical Extraction Techniques

When ADB access is restricted or insufficient, physical extraction becomes necessary:

• Chip-Off Forensics: This involves desoldering the eMMC or UFS flash memory chip from the mainboard and reading its contents directly using specialized hardware readers. This method provides a raw, bit-for-bit image of the storage, circumventing OS-level protections.
• JTAG/UART/ISP: If available, these debug ports can provide low-level access to the bootloader or memory. JTAG (Joint Test Action Group) can enable memory dumping or direct filesystem access. In-System Programming (ISP) allows direct communication with the flash memory chip without desoldering.

These methods require advanced technical skills, specialized equipment, and often lead to vehicle disassembly.

Identifying and Extracting Key Forensic Artifacts

Once access is established, the next phase involves identifying and extracting specific data artifacts.

User and Application Data

Similar to standard Android, user-specific and application data reside primarily in the `/data` partition. Key locations and types of data include:

• User Profiles: Configuration and user IDs within `/data/system/users/`.
• Application Databases: Many apps store data in SQLite databases, typically under `/data/data/<package_name>/databases/` or `/data/user/0/<package_name>/databases/`.
• Shared Preferences and Files: XML files in `/data/data/<package_name>/shared_prefs/` and other files within `/data/data/<package_name>/files/` often contain configuration, session tokens, or cached data.

# Pull a common settings databaseadb pull /data/data/com.android.settings/databases/settings.db .# Pull a potential navigation history database (example for Google Maps)adb pull /data/user/0/com.google.android.apps.maps/databases/history.db .

System Logs and Events

Logs provide a chronological record of system activities, user interactions, and potential anomalies.

• Logcat: Comprehensive Android logging. `adb logcat -d` dumps the entire buffer.
• Kernel Logs: `dmesg` output provides kernel-level events and boot information.
• Car Service Logs: Specific logs related to vehicle properties and interactions.
• Crash Dumps: Located in `/data/tombstones/` or `/data/anr/` for application not responding errors, useful for identifying software stability issues or deliberate tampering.

# Dump all current logcat entries to a fileadb logcat -d > logcat_full.txt# Get kernel ring buffer messagesadb shell dmesg > dmesg_kernel.txt

Vehicle-Specific Data through Car Service

The Car Service exposes vehicle properties via the VHAL. While direct querying of current values is possible programmatically, historical data is more relevant for forensics.

• VIN (Vehicle Identification Number): Often available via `VehiclePropertyIds.VEHICLE_PROPERTY_VIN`.
• Odometer Readings: Historical odometer values can indicate mileage discrepancy.
• Speed and Location Data: While raw GPS data is available, applications often store parsed location history.
• Gear Position, Fuel Level, Tire Pressure: These and many other vehicle properties can be accessed. Persistent storage of these values by the OS or specific apps is key.

Forensic analysis focuses on finding where applications or system services persist these vehicle properties, typically in SQLite databases or proprietary log formats.

Location Data and Connectivity History

• GPS History: Mapping applications are prime sources, but the Android location services also maintain a history. Look for `/data/data/com.google.android.gms/databases/snet_content.db` or similar in Google Play Services.
• Wi-Fi Connections: `/data/misc/wifi/wpa_supplicant.conf` or related database files store configured Wi-Fi networks. Event logs can indicate connection times.
• Bluetooth Pairings: `/data/misc/bluetooth/` contains pairing information and MAC addresses of connected devices.

Tools and Techniques for Artifact Analysis

1. Filesystem and Database Analysis

• `adb pull`/`dd`: For extracting data. `dd` is used for raw disk imaging after gaining root or physical access.
• SQLite Browser: Tools like DB Browser for SQLite are essential for examining application databases.
• Hex Editors: For inspecting raw binary files and unallocated space.
• `strings` utility: Can extract human-readable strings from any file, sometimes revealing hidden data.

2. Application Decompilation

Extracting APKs from `/data/app/` and using tools like `apktool` for resource extraction and `dex2jar` + JD-GUI/Ghidra for Java code decompilation can help understand how an application processes and stores data, aiding in identifying new artifact locations.

# Pull an APKadb pull /data/app/com.example.app-1/base.apk .# Decompile the APKapktool d base.apk

3. Specialized Forensic Tools

While general mobile forensic tools (e.g., Cellebrite, Magnet Forensics) might have limited direct AAOS support, they can often parse extracted Android filesystems. However, manual analysis and scripting are frequently required due to the unique automotive customizations.

Practical Example: Extracting Navigation History

Let’s outline a simplified process for extracting and examining navigation history, assuming ADB access is available and the system is not encrypted or heavily secured against user data access.

1. Connect via ADB:

   adb connect <VEHICLE_IP_ADDRESS>:5555

2. Identify the Target Application Package:

   Determine the package name of the navigation application. For Google Maps, it’s typically `com.google.android.apps.maps`.

   adb shell pm list packages | grep maps

3. Pull Relevant Database Files:

   Locate and pull the application’s database files from the `/data/user/0/<package_name>/databases/` directory. You might need root access for this, or the application might expose world-readable files.

   # Requires root for /data/user/0/adb shell su -c 'cp /data/user/0/com.google.android.apps.maps/databases/history.db /sdcard/history.db'adb pull /sdcard/history.db .

4. Analyze the Database:

   Use a SQLite browser to open `history.db`. Investigate tables like `recent_searches`, `directions_history`, or `destinations`. These tables often contain timestamps, search queries, latitude/longitude coordinates, and destination names.

   # Open with a SQLite browser e.g.sqlitebrowser history.db

   Within the browser, execute SQL queries to retrieve specific information. For instance, to view recent searches:

   SELECT * FROM recent_searches ORDER BY timestamp DESC;

Challenges and Future Outlook

Forensic analysis of AAOS presents several challenges:

• OEM Customizations: Each vehicle manufacturer implements AAOS differently, leading to variations in hardware, software, and data storage locations.
• Security Measures: Verified Boot, device encryption (FDE/FBE), and SELinux policies can significantly hinder access and extraction.
• Root Access: Obtaining root on a production AAOS device is often difficult and may void warranties or trigger security features.
• Live Systems: Analyzing a live AAOS system poses risks of data alteration. Offline analysis from a physical image is always preferred.

As AAOS evolves, so will its forensic landscape. Future developments may include standardized forensic APIs, but for now, investigators must rely on deep technical knowledge of Android internals and automotive systems.

Conclusion

Android Automotive OS is rapidly becoming a central component of modern vehicles, turning them into rich data repositories. The ability to forensically analyze these systems is paramount for digital investigators. By understanding the AAOS architecture, leveraging ADB, and employing physical extraction techniques, investigators can uncover a wealth of forensic artifacts, from navigation history and user preferences to system events and vehicle-specific data. While challenges persist due to OEM variations and security features, the methods outlined here provide a robust framework for approaching AAOS investigations, ensuring critical digital evidence can be successfully recovered and analyzed.