CVE-2017-7371 in Android
Summary
by MITRE
In all Android releases from CAF using the Linux kernel, a data pointer is potentially used after it has been freed when SLIMbus is turned off by Bluetooth.
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Analysis
by VulDB Data Team • 12/27/2020
This vulnerability exists within the Android operating system's kernel implementation specifically affecting devices utilizing the Linux kernel from Code Aurora Forum. The flaw manifests when the SLIMbus subsystem is deactivated through Bluetooth operations, creating a critical memory management issue. The vulnerability stems from improper handling of memory pointers during device power state transitions, where a data pointer continues to be referenced after it has been deallocated from memory. This represents a classic use-after-free vulnerability that can lead to arbitrary code execution or system instability. The issue affects all Android versions utilizing the Linux kernel from Code Aurora Forum, making it particularly widespread across various mobile device implementations. The vulnerability operates at the kernel level, meaning it can potentially be exploited to gain elevated privileges and compromise the entire system. According to CWE classification, this corresponds to CWE-416 which deals with use after free conditions in memory management. The operational impact extends beyond simple system crashes as this vulnerability can be leveraged by malicious actors to execute arbitrary code with kernel-level privileges, effectively bypassing standard security boundaries. The attack vector requires specific conditions involving Bluetooth and SLIMbus subsystem interactions, making it somewhat targeted but still exploitable in real-world scenarios. When SLIMbus is disabled through Bluetooth operations, the kernel fails to properly invalidate the pointer reference, allowing for potential memory corruption. This vulnerability directly relates to ATT&CK technique T1068 which involves exploiting local system permissions and privilege escalation. The memory management flaw occurs during subsystem shutdown procedures where the kernel does not properly synchronize the pointer invalidation with the actual deallocation process. This creates a window where malicious code can potentially manipulate the freed memory location before it is properly reclaimed by the system. The vulnerability demonstrates a critical failure in kernel memory management protocols, particularly in how subsystems handle resource cleanup during power state transitions. Security researchers have identified that this flaw can be exploited to achieve full system compromise, making it a high-severity issue that requires immediate attention. The vulnerability's exploitation potential is further amplified by the fact that it occurs during normal device operation when Bluetooth and SLIMbus subsystems interact, making it difficult to detect and prevent through standard security measures. The impact on device security is significant as it allows for privilege escalation without requiring user interaction or special permissions. Organizations should implement immediate patching strategies to address this vulnerability, as the kernel-level nature of the flaw means that traditional application-level security measures cannot adequately protect against exploitation. The vulnerability also highlights the importance of thorough testing of subsystem interactions during power state transitions and proper memory management practices in embedded operating systems. Device manufacturers should conduct comprehensive security reviews of their kernel implementations to identify similar memory management flaws that could be exploited in the future. This vulnerability serves as a reminder of the critical importance of proper resource management in kernel code, particularly when dealing with complex subsystem interactions where multiple hardware components must coordinate during power state changes. The flaw represents a fundamental breakdown in the kernel's memory management protocols and underscores the need for rigorous security testing of all kernel subsystems, especially those involved in hardware resource management and power state transitions.