Introduction

As Android Automotive OS (AAOS) becomes the foundational operating system for an increasing number of modern vehicles, its role in providing a rich user experience extends into critical data generation. For forensic investigators, this data — encompassing telemetry, infotainment interactions, and system logs — offers an invaluable digital footprint for reconstructing events leading up to, during, and after an incident. This expert-level guide delves into the methodologies for extracting, analyzing, and interpreting AAOS logs to uncover crucial evidence.

Understanding AAOS Logging Mechanisms

AAOS, built upon the standard Android framework, inherits its robust logging infrastructure while adding vehicle-specific logging capabilities. Understanding where and how different types of logs are generated is the first step in effective forensic analysis.

Key Log Types in AAOS

• Logcat: The omnipresent Android logging system captures events from system processes, applications, and the kernel. It’s a primary source for system crashes, application activity, and general device behavior.

• CarService Logs: Unique to AAOS, the CarService manages vehicle-specific hardware and properties via the Vehicle Hardware Abstraction Layer (VHAL). Logs from CarService are critical for understanding vehicle state changes, sensor readings, and infotainment system interactions (e.g., HVAC controls, gear selection, speed).

• Telemetry & Event Logs: Beyond standard logcat, AAOS often implements more structured telemetry logging for performance, diagnostics, and specific vehicle events. These logs can include aggregated sensor data, system health metrics, and high-level user interactions.

• Bugreport: A comprehensive snapshot of the device’s state at a given moment, a bugreport includes all logcat buffers, system services dumps, CPU information, and various system files. It’s an indispensable tool for a holistic view.

Prerequisites for AAOS Forensic Analysis

Accessing AAOS logs typically requires appropriate permissions and tools. The most common method involves using the Android Debug Bridge (ADB).

• Physical Access and ADB: The primary requirement is physical access to the AAOS head unit and an enabled USB debugging interface. In some OEM implementations, secure debugging might require specific authorization or developer mode activation.

• Essential Tools: A workstation with adb installed, a text editor capable of handling large files, and potentially specialized log parsing tools or scripts (e.g., Python, grep, logcat visualizers) are necessary.

Step-by-Step Log Extraction from AAOS Devices

Once ADB access is established, various methods can be employed to extract log data.

Method 1: Direct ADB Logcat Extraction

To capture real-time logs from the device:

adb logcat -b all > aaos_live_log.txt

This command redirects all log buffers (main, system, events, radio, crash) to a file on your host machine. For historical logs, you might need to check persistent log directories.

Method 2: Pulling Specific Log Files

Many critical logs are stored persistently on the device. Common locations include /data/misc/logd for logcat buffers and /data/log or OEM-specific directories for more specialized logs.

adb shell ls /data/misc/logd/ # List persistent log files if available (root may be needed)adb pull /data/misc/logd/logcat aaos_persisted_log.txt # Example: Pulling a persisted logcat buffer

Method 3: Generating a Comprehensive Bugreport

The bugreport command collects a vast amount of diagnostic information, packaging it into a single ZIP file. This is often the most complete initial data acquisition method.

adb bugreport aaos_bugreport_$(date +%Y%m%d_%H%M%S).zip

This command can take several minutes to complete, depending on the device’s activity and storage. The resulting ZIP file will contain various text files, including full logcat output, dumpsys outputs, and other system information.

Method 4: Querying Car Service Properties

For deep insights into vehicle-specific interactions, examining the CarService properties is crucial. The dumpsys command can provide a detailed view of its current state.

adb shell dumpsys activity service CarService > aaos_carservice_dump.txt

To inspect the Vehicle Hardware Abstraction Layer (VHAL) directly, which reports sensor data and vehicle state:

adb shell dumpsys [email protected]::IVehicle/default > aaos_vhal_dump.txt

Note that the VHAL service name might vary slightly based on the Android version and OEM implementation.

Analyzing Key Log Sources for Incident Reconstruction

Once extracted, the raw log data must be systematically analyzed to reconstruct events.

Logcat Analysis

Filtering is paramount due to the sheer volume of logcat data. Focus on tags like