CVE-2021-35068 in Snapdragon Auto
Summary
by MITRE • 02/11/2022
Lack of null check while freeing the device information buffer in the Bluetooth HFP protocol can lead to a NULL pointer dereference in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Voice & Music, Snapdragon Wearables
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Analysis
by VulDB Data Team • 02/16/2022
The vulnerability identified as CVE-2021-35068 represents a critical null pointer dereference flaw within the Bluetooth Hands-Free Profile (HFP) implementation across multiple Qualcomm Snapdragon product lines. This issue manifests during the cleanup process when device information buffers are being freed, specifically lacking proper null pointer validation before memory deallocation operations. The flaw affects a wide range of Snapdragon automotive, connectivity, consumer IoT, industrial IoT, voice/music, and wearable platforms, indicating a systemic issue within Qualcomm's Bluetooth stack implementation.
The technical root cause stems from insufficient input validation within the Bluetooth HFP protocol handler where the system attempts to free memory resources without first verifying whether the buffer pointer is valid or null. When a Bluetooth HFP connection is terminated or when device information is processed, the code path executes a memory deallocation routine that does not perform null pointer checks before dereferencing the device information buffer. This condition creates a scenario where a null pointer is accessed and subsequently dereferenced, leading to system instability and potential exploitation by malicious actors.
From an operational perspective, this vulnerability presents significant risks to automotive and IoT systems that rely on Snapdragon platforms for connectivity and communication functions. The NULL pointer dereference can result in system crashes, application failures, or complete device lockups, particularly in automotive environments where reliable connectivity is critical for safety and functionality. The impact extends beyond simple service disruption to potentially compromising the integrity of vehicle communication systems and IoT device operations. According to CWE classification, this vulnerability maps to CWE-476 which specifically addresses NULL Pointer Dereference, while from an ATT&CK framework perspective, it relates to privilege escalation and system compromise techniques that could be leveraged for persistent access.
The exploitation of this vulnerability requires an attacker to establish a Bluetooth HFP connection and trigger specific conditions that cause the device information buffer to be freed while containing a null value. This could occur through malformed Bluetooth packets or specific sequence of connection events that cause the protocol handler to process invalid data structures. The attack surface is particularly concerning given the widespread deployment of Snapdragon platforms in automotive infotainment systems, industrial monitoring devices, and consumer IoT products where physical access or network-based exploitation could lead to full system compromise.
Mitigation strategies should focus on implementing proper null pointer validation before memory deallocation operations within the Bluetooth HFP protocol handler. System administrators and device manufacturers should prioritize firmware updates from Qualcomm that address this specific null pointer dereference condition. Additional defensive measures include network segmentation to limit Bluetooth communication exposure, implementing Bluetooth connection monitoring to detect anomalous HFP behavior, and deploying intrusion detection systems that can identify potential exploitation attempts. The vulnerability highlights the importance of robust input validation and memory management practices in embedded systems, particularly in automotive and industrial environments where reliability and security are paramount. Organizations should conduct thorough vulnerability assessments of their Snapdragon-based systems and implement monitoring protocols to detect potential exploitation attempts that could lead to system compromise or denial of service conditions.