CVE-2017-9686 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, there is a possible double free/use after free in the SPS driver when debugfs logging is used.
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Analysis
by VulDB Data Team • 01/16/2021
The vulnerability identified as CVE-2017-9686 represents a critical memory corruption issue affecting multiple Android variants including MSM, Firefox OS, and QRD Android platforms that utilize the Linux kernel from Code Aurora Forum. This flaw manifests within the SPS driver component, which serves as a crucial subsystem for managing system performance and power management operations. The vulnerability specifically arises when debugfs logging functionality is actively employed, creating a scenario where memory management operations can become compromised through improper handling of allocated resources.
The technical root cause of this vulnerability stems from improper memory deallocation sequences within the SPS driver's debugfs implementation. When debugfs logging is enabled, the driver performs memory allocation operations that, under certain conditions, can result in the same memory block being freed twice or accessing memory after it has been freed. This double free condition occurs when the kernel's memory management subsystem fails to properly track memory references during debug logging operations, leading to potential memory corruption that can be exploited by malicious actors. The issue falls under the CWE-415 category of double free vulnerabilities, which represents a well-documented class of memory corruption flaws that can lead to arbitrary code execution.
The operational impact of this vulnerability extends across multiple Android platforms and device types that rely on the affected kernel components. Attackers exploiting this weakness could potentially execute arbitrary code with kernel-level privileges, bypassing standard security boundaries and gaining full control over affected devices. This represents a severe threat to device integrity and user data security, particularly in environments where these devices are deployed in enterprise or critical infrastructure settings. The vulnerability's exploitation potential aligns with ATT&CK technique T1068 which involves local privilege escalation through kernel exploits, making it a significant concern for organizations maintaining Android device fleets.
Mitigation strategies for CVE-2017-9686 require immediate implementation of kernel updates from Code Aurora Forum and affected vendors, as well as disabling debugfs logging functionality on production devices where possible. Organizations should also implement monitoring solutions to detect abnormal memory allocation patterns and establish incident response procedures for potential exploitation attempts. The vulnerability highlights the importance of proper memory management practices in kernel drivers and underscores the necessity of thorough security testing for low-level system components. Additionally, device manufacturers should consider implementing runtime protections and memory sanitization techniques to detect and prevent similar issues in future deployments. The affected platforms should undergo comprehensive security assessments to identify potential related vulnerabilities within the same driver subsystems and ensure proper memory management protocols are in place across all kernel components.