CVE-2021-35103 in Snapdragon Auto
Summary
by MITRE • 04/01/2022
Possible out of bound write due to improper validation of number of timer values received from firmware while syncing timers in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Wearables, Snapdragon Wired Infrastructure and Networking
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Analysis
by VulDB Data Team • 04/05/2022
This vulnerability resides in the timer synchronization functionality of multiple Qualcomm Snapdragon product lines including automotive, mobile, compute, and industrial IoT devices. The flaw manifests as an out-of-bounds write condition that occurs when the system fails to properly validate the number of timer values received from firmware during the synchronization process. The vulnerability stems from inadequate input validation mechanisms that do not sufficiently check the bounds of timer data structures before processing. This issue affects a broad range of Qualcomm Snapdragon platforms including automotive systems, mobile devices, wearable technology, and industrial networking equipment. The improper validation allows an attacker to potentially manipulate timer values in a way that could lead to memory corruption and system instability.
The technical implementation of this vulnerability involves the timer synchronization protocol where firmware sends timer configuration data to the system's timer management module. When the system receives timer values from firmware, it does not properly validate whether the received count of timer values exceeds the allocated buffer space or array bounds. This validation failure creates a condition where a maliciously crafted firmware response could cause the system to write timer data beyond the intended memory boundaries. The flaw specifically impacts the timer synchronization process that occurs during system initialization or runtime updates, making it particularly dangerous as it could be exploited during normal operation. According to CWE classification, this represents a CWE-787 Out-of-bounds Write vulnerability, which is a direct consequence of insufficient bounds checking in memory operations.
The operational impact of this vulnerability extends across multiple device categories and could enable several attack vectors. In automotive applications, this flaw could potentially affect vehicle timing systems, brake control, or engine management functions if timer synchronization is critical to these systems. Mobile and wearable devices may experience system crashes, application instability, or potentially more severe memory corruption that could lead to complete device failure. Industrial IoT deployments could face disruptions in timing-critical processes such as sensor data collection, actuator control, or network synchronization. The vulnerability could be exploited by adversaries with access to firmware update mechanisms or through supply chain attacks targeting the firmware components. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving privilege escalation and denial of service through memory corruption, potentially enabling further exploitation.
Mitigation strategies should focus on implementing robust input validation mechanisms for timer synchronization data, including bounds checking and array size verification before processing firmware timer values. System designers should incorporate defensive programming practices such as using safe string and array handling functions, implementing proper buffer overflow protection, and adding runtime checks for timer value counts. Firmware update mechanisms should include integrity verification and access control measures to prevent unauthorized firmware modifications that could exploit this vulnerability. Device manufacturers should consider implementing runtime monitoring for abnormal timer synchronization patterns that could indicate exploitation attempts. Regular security updates and patches should be deployed to address the vulnerability across all affected Snapdragon product lines, with particular attention to automotive and industrial applications where timing precision is critical for safety and operational reliability.