CVE-2021-1919 in Snapdragon Auto
Summary
by MITRE • 09/08/2021
Integer underflow can occur when the RTCP length is lesser than than the actual blocks present in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon IoT, Snapdragon Voice & Music, Snapdragon Wearables
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Analysis
by VulDB Data Team • 09/11/2021
The vulnerability identified as CVE-2021-1919 represents a critical integer underflow condition within the Real-Time Transport Control Protocol implementation of various Qualcomm Snapdragon processor families. This flaw manifests when the RTCP packet length field contains a value that is insufficient to accommodate the actual number of blocks present in the packet structure. The issue affects multiple Snapdragon product lines including automotive, compute, connectivity, consumer IoT, industrial IoT, IoT, voice and music, and wearable devices, indicating a widespread impact across Qualcomm's embedded processor portfolio.
The technical root cause of this vulnerability stems from inadequate input validation within the RTCP packet processing logic where the system fails to properly validate the relationship between the declared packet length and the actual block count. When an attacker crafts a malicious RTCP packet with a length field that underflows relative to the expected block structure, the system's arithmetic operations can produce unexpected results that may lead to memory corruption or buffer overflows. This condition falls under the CWE-191 category of Integer Underflow, which occurs when a calculation produces a result that is smaller than the minimum value representable by the data type, typically resulting in unexpected behavior that can be exploited by malicious actors.
The operational impact of this vulnerability extends across numerous device categories that rely on Snapdragon processors for real-time communication and multimedia processing. In automotive applications, this could potentially affect vehicle communication systems, infotainment networks, or telematics modules where RTCP is used for quality monitoring of media streams. For IoT and wearable devices, the vulnerability may compromise the stability of communication protocols used for data transmission between devices and cloud services. The attack surface is particularly concerning given that RTCP is fundamental to VoIP and streaming applications, where packet corruption could lead to service disruption, data loss, or potentially more severe consequences depending on the specific implementation and use case.
Security professionals should consider this vulnerability in the context of the ATT&CK framework, particularly under the T1059.007 technique for Command and Scripting Interpreter: PowerShell, where such low-level memory corruption vulnerabilities could be leveraged to execute arbitrary code or escalate privileges. The vulnerability's classification as a remote code execution risk through memory corruption mechanisms aligns with ATT&CK's T1203 technique for Exploitation for Client Execution, where attackers could exploit the underflow condition to gain unauthorized access to affected systems. The widespread nature of the affected Snapdragon product families means that mitigation strategies must account for diverse device types and operating environments, including automotive systems, industrial control networks, consumer electronics, and mobile platforms. Organizations should prioritize patch management for affected devices, implement network segmentation to limit exposure, and consider monitoring for anomalous RTCP traffic patterns that could indicate exploitation attempts. The vulnerability underscores the importance of robust input validation and proper integer arithmetic handling in embedded systems where resource constraints may limit the implementation of comprehensive security controls.