CVE-2017-9703 in Android
Summary
by MITRE
In Android for MSM, Firefox OS for MSM, QRD Android, with all Android releases from CAF using the Linux kernel, a race condition in a Camera driver can lead to a Use After Free condition.
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Analysis
by VulDB Data Team • 12/21/2019
The vulnerability identified as CVE-2017-9703 represents a critical race condition flaw within the camera driver component of Android systems running on Qualcomm MSM (Mobile Station Modem) platforms. This issue affects multiple Android variants including standard Android releases from Qualcomm Atheros (CAF), Firefox OS for MSM, and QRD Android implementations. The fundamental problem occurs within the Linux kernel subsystem that manages camera hardware access, creating a scenario where concurrent processes can interfere with each other's memory management operations.
The technical root cause of this vulnerability lies in improper synchronization mechanisms within the camera driver's memory management routines. When multiple processes attempt to access camera hardware resources simultaneously, the driver fails to properly enforce mutual exclusion during critical sections where memory allocations and deallocations occur. This race condition creates a window where a memory block can be freed by one process while another process simultaneously attempts to access the same memory location, resulting in a use-after-free condition. The vulnerability is particularly dangerous because it occurs at the kernel level, allowing malicious actors to potentially escalate privileges and execute arbitrary code with kernel-level permissions.
From an operational impact perspective, this vulnerability poses significant security risks to mobile devices running affected Android variants. Attackers can exploit this condition to gain unauthorized access to device resources, potentially leading to complete system compromise. The use-after-free condition creates opportunities for memory corruption attacks that can be leveraged to execute malicious code, bypass security controls, or escalate privileges. The vulnerability affects devices where camera functionality is utilized, making it particularly concerning for mobile platforms where camera drivers are frequently accessed. Security researchers have classified this issue as high-risk due to its potential for privilege escalation and the kernel-level access it provides to attackers.
The mitigation strategies for CVE-2017-9703 require immediate attention from device manufacturers and system administrators. The primary solution involves applying kernel-level patches that address the race condition in the camera driver's memory management routines. These patches typically implement proper synchronization mechanisms such as mutex locks or semaphores to prevent concurrent access to shared memory resources during critical operations. Additionally, implementing kernel address space layout randomization (KASLR) and other exploit mitigation techniques can help reduce the effectiveness of potential exploitation attempts. Organizations should prioritize updating all affected devices and ensure that security patches are applied promptly, as the vulnerability exists in multiple Android variants and affects various hardware platforms. The fix should be validated through comprehensive testing to ensure that it does not introduce regressions in camera functionality or other system components.
This vulnerability aligns with CWE-362, which describes concurrent execution using shared resource with improper synchronization, and demonstrates characteristics consistent with ATT&CK technique T1068, which involves the exploitation of local privilege escalation vulnerabilities. The race condition in kernel drivers represents a common class of vulnerabilities that security researchers continue to identify in mobile operating systems, emphasizing the critical importance of proper synchronization mechanisms in kernel-level code development and the necessity of thorough security testing for all system components.