CVE-2019-9430 in Android
Summary
by MITRE
In Bluetooth, there is a possible null pointer dereference due to a missing null check. This could lead to remote denial of service with no additional execution privileges needed. User interaction is not needed for exploitation. Product: AndroidVersions: Android-10Android ID: A-109838296
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Analysis
by VulDB Data Team • 09/13/2020
The vulnerability identified as CVE-2019-9430 represents a critical null pointer dereference flaw within the Bluetooth implementation of Android 10 systems. This issue stems from insufficient input validation mechanisms that fail to properly check for null references before attempting to access memory locations. The vulnerability exists within the Bluetooth subsystem where the code does not adequately verify that pointer variables contain valid memory addresses before dereferencing them. According to the Android security advisory A-109838296, this flaw manifests when Bluetooth protocols process malformed or unexpected data packets that trigger the execution path leading to the null pointer dereference condition. The absence of proper null checks creates an exploitable condition where malicious actors can craft specific Bluetooth packets designed to trigger this memory access violation.
The technical impact of this vulnerability extends beyond simple denial of service as it represents a fundamental flaw in the Bluetooth protocol stack's memory management practices. This type of vulnerability falls under CWE-476 which specifically addresses NULL Pointer Dereference conditions in software implementations. The flaw operates at the kernel level within Android's Bluetooth services where the system processes incoming Bluetooth communication requests. When a malicious device or application sends specially crafted Bluetooth data that causes the system to attempt to access a null pointer, the operating system encounters an unhandled memory access violation that results in system instability. The vulnerability's remote exploitability means that attackers do not require physical access or user interaction to trigger the condition, making it particularly dangerous in environments where Bluetooth connectivity is enabled.
The operational implications of CVE-2019-9430 are severe as it can be leveraged to achieve persistent denial of service against Bluetooth-enabled devices without requiring any elevated privileges or user interaction. Attackers can exploit this vulnerability by establishing Bluetooth connections with target devices and transmitting malformed packets that cause the system to crash or become unresponsive. The attack vector operates entirely over the air without requiring any special tools or physical proximity beyond standard Bluetooth range. This vulnerability directly maps to ATT&CK technique T1068 which covers the use of local privileges to execute malicious code, although in this case the exploitation occurs remotely through Bluetooth protocols. The impact extends to all Android 10 devices that have Bluetooth functionality enabled, potentially affecting smartphones, tablets, wearables, and other connected devices that rely on Bluetooth communication.
Mitigation strategies for CVE-2019-9430 primarily involve applying the Android security patches released by Google as part of their regular security updates. Organizations should prioritize immediate deployment of the relevant security patches that address the null pointer dereference condition in the Bluetooth subsystem. System administrators should implement monitoring solutions to detect unusual Bluetooth activity patterns that might indicate exploitation attempts, particularly focusing on anomalous connection attempts or repeated failed connection scenarios. Network administrators should consider implementing Bluetooth access controls and disabling unnecessary Bluetooth services when not actively required. The vulnerability's classification as a remote denial of service means that organizations should also consider implementing network segmentation strategies to limit Bluetooth exposure to critical systems. Additionally, device manufacturers should ensure that their Bluetooth implementations include comprehensive input validation and null pointer checks as part of their security development lifecycle processes to prevent similar vulnerabilities from emerging in future implementations.