CVE-2021-35075 in Snapdragon Auto
Summary
by MITRE • 02/11/2022
Possible null pointer dereference due to lack of WDOG structure validation during registration in Snapdragon Auto, Snapdragon Connectivity, Snapdragon Industrial IOT, Snapdragon Mobile
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Analysis
by VulDB Data Team • 02/16/2022
This vulnerability represents a critical null pointer dereference issue within the watchdog (WDOG) subsystem of Qualcomm's Snapdragon automotive, connectivity, industrial iot, and mobile platforms. The flaw occurs during the registration process of watchdog structures where insufficient validation is performed on the input parameters, potentially allowing malicious actors or faulty code paths to trigger a system crash through null pointer access. The vulnerability stems from inadequate input sanitization and validation mechanisms within the kernel-level watchdog driver implementation, specifically affecting the registration function that handles watchdog structure initialization and registration with the system's watchdog subsystem.
The technical execution of this vulnerability involves a scenario where a watchdog structure pointer is passed to the registration function without proper validation of whether it is null or properly initialized. This allows for a situation where the system attempts to dereference a null pointer during the watchdog registration process, leading to an immediate system crash or potential privilege escalation depending on the execution context. The vulnerability is particularly concerning in automotive and industrial applications where system stability and safety are paramount, as watchdog mechanisms are essential for system monitoring and fault recovery. According to CWE classification, this represents a CWE-476 Null Pointer Dereference, which is a well-known vulnerability pattern that occurs when a program attempts to access a memory location through a pointer that has a value of null. The vulnerability also maps to ATT&CK technique T1068, which involves exploiting local privileges to gain system-level access through kernel vulnerabilities.
The operational impact of this vulnerability extends across multiple Snapdragon platform variants, affecting automotive systems that rely on watchdog functionality for safety-critical operations, industrial IoT devices that require continuous monitoring, and mobile platforms where system reliability is crucial. In automotive contexts, this vulnerability could potentially lead to unintended vehicle system failures, especially in safety-critical applications such as brake systems, airbag deployment, or engine control modules where watchdog timers are essential for system integrity. The affected platforms include various Snapdragon Auto series, Snapdragon Connectivity platforms, Industrial IOT solutions, and mobile device processors, indicating a broad attack surface that spans multiple market segments. Organizations deploying these platforms must consider the potential for denial of service attacks that could render systems inoperable or compromise safety-critical functions. The vulnerability's exploitation requires minimal privileges and can be triggered through kernel-level interactions, making it particularly dangerous in environments where multiple applications or services interact with the watchdog subsystem.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation mechanisms within the watchdog registration functions, ensuring that all structure pointers are properly validated before any dereference operations occur. The recommended approach includes adding explicit null checks and validation routines that verify the integrity of watchdog structures before processing them, along with implementing proper error handling that prevents system crashes. Organizations should prioritize applying official firmware updates from Qualcomm that address the specific null pointer dereference issue in the watchdog subsystem. Additionally, system architects should consider implementing runtime monitoring and anomaly detection for watchdog registration processes to identify potential exploitation attempts. The fix should be implemented at the kernel level where the watchdog registration occurs, ensuring that the WDOG structure validation is robust and comprehensive. System administrators should also conduct thorough security assessments of their deployed Snapdragon platforms to identify any potential variants of this vulnerability that may exist in custom implementations or third-party drivers that interact with the watchdog subsystem.