CVE-2018-13920 in Snapdragon Auto
Summary
by MITRE
Use-after-free condition due to Improper handling of hrtimers when the PMU driver tries to access its events in Snapdragon Auto, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Wearables in MDM9206, MDM9607, MDM9650, MSM8909W, QCS605, Qualcomm 215, SD 425, SD 439 / SD 429, SD 450, SD 625, SD 632, SD 636, SD 712 / SD 710 / SD 670, SD 820A, SD 845 / SD 850, SD 855, SDM439, SDM630, SDM660, SDX24
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Analysis
by VulDB Data Team • 06/15/2020
The vulnerability CVE-2018-13920 represents a critical use-after-free condition that manifests in Qualcomm's Snapdragon automotive and mobile platform ecosystems. This flaw occurs within the PMU (Power Management Unit) driver when attempting to access timer events, specifically involving hrtimers or high-resolution timers. The issue stems from improper handling of timer resources during driver operations, creating a scenario where memory locations become accessible after they have been freed, potentially allowing malicious code execution or system instability.
The technical implementation of this vulnerability involves the interaction between the PMU driver and the kernel's timer subsystem. When the PMU driver attempts to access its associated timer events, the system fails to properly validate or synchronize access to these timer resources. This improper resource management creates a window where freed memory structures can still be referenced, leading to unpredictable behavior and potential code execution. The flaw affects multiple generations of Qualcomm's Snapdragon chipsets, spanning from the MDM9206 through the SDM660 platforms, indicating a widespread impact across various automotive and mobile device categories.
From an operational perspective, this vulnerability presents significant risks to systems utilizing affected Snapdragon platforms, particularly in automotive applications where the Snapdragon Auto ecosystem is deployed. The use-after-free condition could enable attackers to execute arbitrary code with kernel privileges, potentially compromising the entire system's security posture. The impact extends beyond simple system crashes to include potential data breaches, unauthorized access to sensitive vehicle systems, and disruption of critical automotive functions. Attackers could exploit this vulnerability to gain persistent access to vehicle systems or consumer IoT devices, making it particularly concerning for automotive cybersecurity frameworks.
The vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software development, and represents a classic example of improper resource management in kernel drivers. From an ATT&CK framework perspective, this flaw could be leveraged for privilege escalation and persistence within automotive environments, potentially mapping to techniques involving driver manipulation and kernel exploitation. The affected platforms span multiple automotive and consumer categories, including the Snapdragon Auto, Consumer IOT, Industrial IOT, Mobile, and Wearables product lines, indicating that mitigation efforts must address a broad ecosystem of devices. Organizations should implement immediate firmware updates from Qualcomm, monitor for exploitation attempts, and consider network segmentation to limit potential lateral movement within affected automotive networks.
Qualcomm has addressed this vulnerability through firmware updates and driver modifications that properly handle timer resource cleanup and access synchronization. The fix involves implementing proper reference counting and synchronization mechanisms within the PMU driver to prevent access to freed timer resources. Security teams should prioritize patch deployment across all affected Snapdragon platforms, particularly in automotive environments where the risk of exploitation could lead to serious safety implications. The vulnerability serves as a reminder of the critical importance of proper resource management in kernel drivers and highlights the need for comprehensive security testing of automotive platform components. Organizations should also consider implementing runtime monitoring solutions to detect potential exploitation attempts and maintain continuous vulnerability assessment programs for their automotive and IoT device fleets.