CVE-2017-9685 in Android
Summary
by MITRE
In all Qualcomm products with Android releases from CAF using the Linux kernel, a race condition in a WLAN driver can lead to a Use After Free condition.
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Analysis
by VulDB Data Team • 11/09/2019
The vulnerability identified as CVE-2017-9685 represents a critical race condition flaw within the WLAN driver component of Qualcomm Android devices running Linux kernel versions from the Common Audio Framework. This issue stems from improper synchronization mechanisms during memory management operations within the wireless networking subsystem. The race condition occurs when multiple threads or processes attempt to access and modify shared memory resources simultaneously without adequate protective measures, creating a window where memory allocated to one process can be freed while another process still references it. This fundamental flaw in concurrent execution handling directly violates established security principles for memory management in kernel space environments.
The technical exploitation of this vulnerability manifests as a Use After Free condition, where memory that has been deallocated is still accessed by the system, potentially leading to arbitrary code execution or system instability. The flaw specifically affects devices utilizing Qualcomm's Linux kernel implementations, making it particularly widespread across the Android ecosystem where Qualcomm processors are prevalent. The race condition typically occurs during dynamic memory allocation and deallocation processes within the WLAN driver module, where insufficient locking mechanisms fail to prevent simultaneous access to the same memory segment. This vulnerability maps directly to CWE-367 which defines the weakness of Time-of-Check to Time-of-Use errors, and represents a classic example of improper resource management in kernel-level code.
The operational impact of CVE-2017-9685 extends beyond simple system crashes or instability, as it provides potential attackers with a pathway for privilege escalation and persistent system compromise. An attacker who can trigger the race condition may gain the ability to execute malicious code with kernel-level privileges, effectively bypassing standard user-space security controls and access restrictions. This vulnerability is particularly concerning because it operates at the kernel level within the wireless networking stack, making it difficult to detect and mitigate through conventional application-level security measures. The attack surface is broad given the widespread adoption of Qualcomm chipsets in Android devices, potentially affecting millions of users across various device categories including smartphones, tablets, and IoT devices. The vulnerability's exploitation can result in complete system compromise, data exfiltration, and persistent backdoor access.
Mitigation strategies for CVE-2017-9685 require immediate patch deployment from device manufacturers and carriers, as Qualcomm has released firmware updates specifically addressing the race condition in the WLAN driver module. System administrators should prioritize updating all affected devices to the latest security patches and firmware versions, particularly for enterprise environments where mobile device management solutions can automate these updates. Network monitoring systems should be configured to detect anomalous wireless behavior patterns that might indicate exploitation attempts, while endpoint protection solutions should include kernel-level integrity monitoring to detect unauthorized modifications to the WLAN driver components. The vulnerability demonstrates the critical importance of proper synchronization mechanisms in kernel development and aligns with ATT&CK technique T1059.007 for kernel rootkits and T1068 for exploitation of remote services. Organizations should also implement device hardening practices that limit wireless functionality when not required, reducing the attack surface and providing additional defensive layers against potential exploitation of this memory management flaw.