CVE-2017-9704 in Android
Summary
by MITRE
In all android releases(Android for MSM, Firefox OS for MSM, QRD Android) from CAF using the linux kernel, There is no synchronization between msm_vb2 buffer operations which can lead to use after free.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 04/22/2020
The vulnerability identified as CVE-2017-9704 represents a critical synchronization flaw within the Linux kernel implementations used across various Android platforms including MSM variants, Firefox OS for MSM, and QRD Android systems. This issue stems from the absence of proper coordination mechanisms during msm_vb2 buffer operations, which are fundamental components in video buffer management for mobile devices. The underlying problem manifests in the kernel's handling of video buffer operations where multiple processes or threads access shared memory regions without adequate locking or synchronization protocols, creating a dangerous race condition scenario.
The technical flaw specifically exploits the lack of proper mutex or spinlock mechanisms when managing video buffer operations through the msm_vb2 subsystem. When multiple threads attempt to access or manipulate the same video buffer simultaneously, the kernel fails to enforce proper ordering and coordination, leading to situations where a buffer that has been freed by one thread can still be accessed by another thread. This classic use-after-free vulnerability occurs because the kernel does not properly track buffer lifecycle management or enforce exclusive access during critical buffer operations, allowing for memory corruption and potential privilege escalation scenarios.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can enable malicious actors to execute arbitrary code with elevated privileges. Attackers can exploit this flaw by carefully orchestrating buffer allocation and deallocation sequences to trigger the use-after-free condition, potentially leading to complete system compromise. The vulnerability affects a wide range of mobile devices that rely on Qualcomm's MSM (Mobile Services Module) platforms, making it particularly concerning given the widespread adoption of these chipsets in smartphones and tablets. The attack surface is further expanded due to the kernel-level nature of the flaw, which operates at a privileged execution level where successful exploitation can result in persistent system compromise and data theft.
Mitigation strategies for CVE-2017-9704 require immediate kernel-level patches that implement proper synchronization mechanisms around msm_vb2 buffer operations. System administrators and device manufacturers should prioritize applying security updates that introduce appropriate locking protocols and buffer lifecycle management. The fix typically involves adding mutex or spinlock mechanisms to ensure exclusive access during buffer allocation, deallocation, and usage phases. Additionally, implementing proper buffer validation checks and memory management protocols can help prevent the exploitation of race conditions. Organizations should also consider deploying runtime monitoring solutions that can detect anomalous buffer access patterns and potential exploitation attempts, while maintaining strict compliance with security standards such as those outlined in the CWE catalog under category 362 for race conditions and category 119 for buffer overflows. The ATT&CK framework would classify this vulnerability under privilege escalation techniques and kernel-mode rootkits, emphasizing the need for comprehensive security measures including kernel patching, memory protection enhancements, and regular security assessments to prevent exploitation attempts targeting these fundamental kernel subsystems.