CVE-2015-9043 in Android
Summary
by MITRE
In all Qualcomm products with Android releases from CAF using the Linux kernel, a NULL pointer can be dereferenced upon the expiry of a timer.
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Analysis
by VulDB Data Team • 11/08/2019
The vulnerability identified as CVE-2015-9043 represents a critical NULL pointer dereference flaw within the Linux kernel implementation used in Qualcomm products running Android versions from the Common Android Framework. This issue manifests when a timer expires, creating a condition where the system attempts to access a memory location that has not been properly initialized or allocated, resulting in a potential system crash or unexpected behavior. The flaw exists at the kernel level and affects all Qualcomm Snapdragon processors that utilize the Linux kernel as their underlying operating system foundation, making it particularly concerning given the widespread adoption of Qualcomm chipsets in mobile devices and embedded systems. The vulnerability stems from inadequate input validation and error handling within the timer subsystem, where the kernel fails to properly check for NULL pointer conditions before attempting memory access operations.
From a technical perspective, this vulnerability operates through a classic null pointer dereference pattern that falls under CWE-476, which specifically addresses NULL pointer dereference conditions in software implementations. The flaw occurs when a timer callback function executes upon expiration, but the underlying data structure or pointer that should contain valid memory references has been set to NULL due to improper cleanup or initialization sequences. This type of vulnerability is particularly dangerous in kernel space because it can lead to complete system instability, potential privilege escalation, or even allow attackers to execute arbitrary code with kernel-level privileges. The timing aspect of this vulnerability makes it particularly challenging to exploit reliably, as it requires precise control over system resources and timing conditions to trigger the specific sequence that leads to the NULL pointer dereference.
The operational impact of CVE-2015-9043 extends beyond simple system crashes, as it represents a fundamental reliability issue that can affect device availability and user experience across numerous Qualcomm-based devices. Devices utilizing affected kernel versions may experience unexpected reboots, application failures, or complete system lockups when specific timing conditions are met. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1068, which involves the exploitation of legitimate credentials and system access to gain elevated privileges. The vulnerability can potentially be leveraged in privilege escalation scenarios where an attacker might exploit the kernel-level NULL pointer dereference to execute malicious code with system-level privileges, particularly in environments where kernel exploits are possible. The widespread nature of Qualcomm's Snapdragon processors in mobile devices, tablets, and embedded systems means that this vulnerability affects a substantial portion of the mobile computing ecosystem.
Mitigation strategies for this vulnerability require immediate kernel updates and patches from device manufacturers, as the flaw exists at the core operating system level. Organizations and users should prioritize applying security patches released by Qualcomm and device vendors to address the underlying kernel implementation issues. The fix typically involves adding proper NULL pointer checks before memory access operations within timer callback functions, ensuring that all pointers are validated before dereferencing. Additionally, system administrators should implement monitoring solutions to detect potential exploitation attempts and maintain regular security updates to prevent similar vulnerabilities from emerging in the future. The vulnerability highlights the critical importance of proper kernel development practices and thorough testing of timer and resource management subsystems, particularly in mobile environments where system stability and security are paramount considerations.