CVE-2019-9426 in Android
Summary
by MITRE
In the Android kernel in Bluetooth there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 12/13/2023
The vulnerability identified as CVE-2019-9426 represents a critical out-of-bounds write flaw within the Android kernel's Bluetooth implementation that fundamentally compromises system security integrity. This issue resides in the kernel-level Bluetooth subsystem where proper input validation mechanisms have been omitted, creating a scenario where malicious code can write data beyond the allocated memory boundaries. The vulnerability specifically affects the kernel's handling of Bluetooth-related data structures, where insufficient bounds checking allows for arbitrary memory corruption that can be exploited by malicious actors. The flaw demonstrates characteristics consistent with CWE-787 Out-of-bounds Write, which occurs when a program writes to memory beyond the allocated buffer boundaries, potentially leading to system instability or complete compromise.
The technical execution of this vulnerability requires an attacker to possess system execution privileges, which aligns with the privilege escalation vector described in the CVE. However, the absence of user interaction requirements makes this particularly dangerous as it can be exploited automatically without any human intervention. The kernel-level nature of the flaw means that exploitation can directly target the most privileged execution environment where the Bluetooth subsystem operates, allowing for complete system compromise. The out-of-bounds write condition creates opportunities for attackers to overwrite critical kernel data structures or function pointers, potentially enabling them to gain full control over the device's operating system. This vulnerability operates at the core of Android's security model where kernel-level integrity is paramount for maintaining device security boundaries.
The operational impact of CVE-2019-9426 extends beyond simple privilege escalation, as it represents a fundamental weakness in the Android kernel's memory management and input validation processes. When exploited, this vulnerability can lead to complete system compromise where attackers can execute arbitrary code with the highest system privileges, effectively bypassing all standard security controls. The implications are severe for mobile devices as they represent a persistent threat that can be leveraged to establish persistent backdoors, exfiltrate sensitive data, or deploy additional malicious payloads. From an attacker's perspective, the lack of user interaction requirements makes this vulnerability particularly attractive for automated exploitation campaigns, as it can be triggered silently during normal Bluetooth operations without any user awareness.
Mitigation strategies for this vulnerability must focus on immediate kernel-level patches and updates that implement proper bounds checking mechanisms within the Bluetooth subsystem. The recommended approach involves applying security patches from Android Security Bulletins that specifically address the memory validation issues in the kernel's Bluetooth implementation. Organizations should prioritize patch deployment across all affected Android devices and ensure that the updated kernel versions include comprehensive input validation routines that prevent out-of-bounds memory operations. Additionally, security monitoring should be enhanced to detect anomalous Bluetooth-related kernel activities that might indicate exploitation attempts. The vulnerability's classification under ATT&CK technique T1068 for Local Privilege Escalation and T1543 for Create or Modify System Process highlights the need for comprehensive endpoint protection measures that monitor kernel-level activities and prevent unauthorized privilege escalation attempts. Network segmentation and Bluetooth service disablement on critical systems can serve as temporary mitigations while full patches are deployed.