CVE-2023-40129 Overview
CVE-2023-40129 is a heap buffer overflow vulnerability in the Android Bluetooth stack, specifically within the build_read_multi_rsp function of gatt_sr.cc. This vulnerability enables attackers within wireless range to achieve remote code execution on vulnerable Android devices without requiring user interaction or additional execution privileges.
Critical Impact
Remote code execution via Bluetooth on Android devices running versions 12.0, 12.1, and 13.0 with no user interaction required. Attackers within adjacent network range can potentially gain full control of the device.
Affected Products
- Google Android 12.0
- Google Android 12.1
- Google Android 13.0
Discovery Timeline
- October 27, 2023 - CVE-2023-40129 published to NVD
- November 21, 2024 - Last updated in NVD database
Technical Details for CVE-2023-40129
Vulnerability Analysis
This vulnerability is classified as CWE-787 (Out-of-Bounds Write) and manifests as a heap buffer overflow in the Android Bluetooth Generic Attribute Profile (GATT) server implementation. The flaw exists in the build_read_multi_rsp function within the gatt_sr.cc source file, which handles GATT read multiple response operations.
The vulnerability allows an attacker within Bluetooth range to trigger an out-of-bounds write condition by sending specially crafted GATT requests. Since the overflow occurs on the heap, successful exploitation could allow arbitrary code execution with the privileges of the Bluetooth service process. The attack can be conducted without any user interaction, making it particularly dangerous as victims would have no warning before compromise.
Root Cause
The root cause stems from improper bounds checking in the build_read_multi_rsp function when constructing responses to GATT read multiple requests. When processing these requests, the function fails to properly validate the size of incoming data against the allocated buffer space, allowing heap memory corruption to occur through a write operation that exceeds the intended buffer boundaries.
Attack Vector
The attack vector is via Adjacent Network, meaning an attacker must be within Bluetooth radio range of the target device. The attacker sends malicious GATT protocol requests to the vulnerable device, triggering the heap buffer overflow. Since no user interaction is required and no additional privileges are needed for exploitation, an attacker can silently compromise devices merely by being in proximity with Bluetooth enabled.
The exploitation flow involves:
- Attacker establishes a Bluetooth connection with the target device
- Attacker initiates GATT read multiple requests with crafted payloads
- The build_read_multi_rsp function processes the request without proper bounds validation
- Heap buffer overflow occurs, corrupting adjacent memory structures
- Attacker achieves code execution within the Bluetooth service context
Detection Methods for CVE-2023-40129
Indicators of Compromise
- Unusual Bluetooth connection attempts or pairing requests from unknown devices
- Bluetooth service crashes or unexpected restarts on Android devices
- Anomalous GATT protocol traffic patterns, particularly multiple read requests with abnormal sizes
- Memory corruption signs in Bluetooth-related processes such as com.android.bluetooth
Detection Strategies
- Monitor Android system logs for Bluetooth service crashes or segmentation faults in gatt_sr.cc related functions
- Deploy mobile threat detection solutions capable of identifying anomalous Bluetooth protocol behavior
- Implement network-level Bluetooth traffic analysis where infrastructure permits
- Use SentinelOne Singularity Mobile to detect exploitation attempts and suspicious Bluetooth activity
Monitoring Recommendations
- Enable verbose logging for Bluetooth services on critical Android devices
- Monitor for unexpected Bluetooth service restarts in enterprise mobile device management (MDM) solutions
- Implement alerting for multiple failed Bluetooth connection attempts from the same source
- Track Android security patch levels across device fleet to identify unpatched systems
How to Mitigate CVE-2023-40129
Immediate Actions Required
- Apply the Android Security Bulletin October 2023 patches immediately on all affected devices
- Disable Bluetooth on devices that cannot be immediately patched when not actively in use
- Limit Bluetooth discoverability to "hidden" mode to reduce attack surface
- Ensure enterprise devices are enrolled in MDM with mandatory security update policies
Patch Information
Google has released patches addressing this vulnerability in the October 2023 Android Security Bulletin. The fix is available in the Android Bluetooth module with commit hash c0151aa3ba76c785b32c7f9d16c98febe53017b1. Organizations should apply the security patch level dated 2023-10-01 or later to remediate this vulnerability.
For detailed patch information, refer to:
Workarounds
- Disable Bluetooth entirely on devices where it is not required for business operations
- Configure devices to non-discoverable mode to prevent unsolicited connection attempts
- Implement physical security controls in high-risk environments to limit attacker proximity
- Use SentinelOne Singularity Mobile for runtime protection against exploitation attempts on mobile endpoints
# ADB command to disable Bluetooth via device policy (requires root or MDM)
adb shell settings put global bluetooth_on 0
# Check current Android security patch level
adb shell getprop ro.build.version.security_patch
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
