CVE-2023-20954: Google Android RCE Vulnerability

CVE-2023-20954 Overview

CVE-2023-20954 is a critical out-of-bounds write vulnerability in the Android operating system's Bluetooth Service Discovery Protocol (SDP) implementation. The flaw exists in the SDP_AddAttribute function within sdp_db.cc, where an incorrect bounds check allows an attacker to write data beyond allocated memory boundaries. This vulnerability enables remote code execution without requiring any user interaction or additional execution privileges, making it particularly dangerous for Android device users.

Critical Impact

This vulnerability allows attackers to achieve remote code execution on affected Android devices via Bluetooth without any user interaction, potentially leading to complete device compromise.

Affected Products

• Google Android 11.0
• Google Android 12.0
• Google Android 12.1 (Android 12L)
• Google Android 13.0

Discovery Timeline

• 2023-03-24 - CVE-2023-20954 published to NVD
• 2025-02-25 - Last updated in NVD database

Technical Details for CVE-2023-20954

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-Bounds Write), a memory corruption flaw that occurs when the application writes data past the end or before the beginning of an intended buffer. In the context of CVE-2023-20954, the SDP_AddAttribute function in Android's Bluetooth stack fails to properly validate the bounds of input data before writing it to memory.

The Bluetooth SDP component is responsible for discovering services offered by nearby Bluetooth devices. When processing malformed SDP attributes, the flawed bounds checking logic allows an attacker to corrupt adjacent memory regions. Since this occurs in the Bluetooth system service running with elevated privileges, successful exploitation grants attackers significant control over the affected device.

The network-accessible nature of this vulnerability, combined with no requirement for user interaction or authentication, creates an ideal attack scenario for threat actors targeting mobile devices in proximity.

Root Cause

The root cause of CVE-2023-20954 lies in the improper bounds validation within the SDP_AddAttribute function in sdp_db.cc. When adding attributes to the SDP database, the function performs an incorrect bounds check that fails to properly account for the size of incoming data relative to the allocated buffer space. This oversight allows maliciously crafted SDP packets to trigger writes beyond the allocated memory region, corrupting adjacent memory structures.

Attack Vector

The attack vector for this vulnerability is network-based, specifically over Bluetooth. An attacker within Bluetooth range of a vulnerable Android device can send specially crafted SDP packets designed to exploit the improper bounds check. The attack does not require any privileges on the target device, nor does it require the victim to take any action such as accepting a pairing request or opening an application.

The exploitation flow involves:

1. Attacker identifies a vulnerable Android device within Bluetooth range
2. Malicious SDP packets are crafted with oversized or malformed attribute data
3. The packets trigger the out-of-bounds write condition in SDP_AddAttribute
4. Memory corruption leads to arbitrary code execution in the context of the Bluetooth service

Since no verified code examples are available for this vulnerability, researchers and security teams should refer to the Android Security Bulletin March 2023 for technical details regarding the specific implementation flaw and the corresponding patch.

Detection Methods for CVE-2023-20954

Indicators of Compromise

• Unusual Bluetooth service crashes or restarts on Android devices
• Unexpected system behavior or stability issues following Bluetooth connections
• Memory corruption indicators in system logs related to sdp_db.cc or Bluetooth services
• Suspicious Bluetooth connection attempts from unknown devices

Detection Strategies

• Monitor Android system logs for crashes or exceptions in Bluetooth-related processes
• Implement network detection rules for malformed SDP packets on enterprise MDM solutions
• Deploy endpoint protection solutions capable of detecting memory corruption attempts
• Utilize SentinelOne's behavioral AI to identify exploitation attempts targeting the Android Bluetooth stack

Monitoring Recommendations

• Enable verbose Bluetooth logging on managed Android devices to capture potential exploitation attempts
• Monitor for unusual Bluetooth pairing activity or service discovery requests
• Implement alerting for Bluetooth service crashes that may indicate exploitation attempts
• Review device logs for any evidence of unauthorized code execution following Bluetooth activity

How to Mitigate CVE-2023-20954

Immediate Actions Required

• Apply the March 2023 Android Security Patch immediately on all affected devices
• Disable Bluetooth on devices that cannot be immediately patched when not in active use
• Implement network segmentation to limit Bluetooth exposure in sensitive environments
• Deploy mobile device management (MDM) solutions to enforce security policies and patch compliance

Patch Information

Google addressed this vulnerability in the Android Security Bulletin March 2023. The security patch level of 2023-03-01 or later includes the fix for CVE-2023-20954 (Android ID: A-261867748). Organizations should ensure all managed Android devices are updated to at least this patch level. Device manufacturers may have released corresponding updates for their specific Android implementations.

Workarounds

• Disable Bluetooth when not actively required to reduce the attack surface
• Keep Bluetooth in non-discoverable mode when enabled to limit exposure
• Avoid using Bluetooth in public or untrusted environments until patches are applied
• Implement strict MDM policies to enforce Bluetooth usage restrictions on corporate devices

# Android ADB command to check current security patch level
adb shell getprop ro.build.version.security_patch

# Verify Bluetooth service status
adb shell dumpsys bluetooth_manager | grep "enabled"

# Disable Bluetooth via ADB (requires appropriate permissions)
adb shell settings put global bluetooth_on 0