CVE-2020-11243 in Snapdragon Auto
Summary
by MITRE • 04/07/2021
RRC sends a connection establishment success to NAS even though connection setup validation returns failure and leads to denial of service in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Mobile
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 04/11/2021
The vulnerability identified as CVE-2020-11243 represents a critical flaw in the Radio Resource Control layer of Qualcomm Snapdragon automotive and mobile platforms. This issue manifests when the RRC layer incorrectly processes connection establishment responses, specifically sending a successful connection establishment message to the Network Access Server even when the underlying connection setup validation has failed. The flaw exists within the mobile network protocol stack and affects multiple Snapdragon product lines including automotive, compute, connectivity, and mobile platforms. The improper state handling creates a scenario where the system believes a connection has been successfully established while in reality the connection setup validation has failed, leading to inconsistent network state management and potential service disruption.
The technical root cause of this vulnerability stems from inadequate error handling within the RRC protocol implementation. When the RRC layer performs connection setup validation, it should properly validate all required parameters and return appropriate failure indicators when validation fails. However, in this case, the system bypasses proper validation error propagation and instead sends a connection establishment success message to the NAS layer. This behavior violates fundamental protocol state management principles and creates a condition where the network stack operates with incorrect assumptions about connection status. The flaw demonstrates a classic case of insufficient input validation and error state handling, which aligns with CWE-252, which describes "Unchecked Return Value" as a common vulnerability pattern where developers fail to check the return values of functions that may indicate failure conditions.
From an operational impact perspective, this vulnerability creates a significant denial of service condition that can affect automotive connectivity systems and mobile devices. When the RRC layer incorrectly signals successful connection establishment, downstream network services may begin to operate under false assumptions about network connectivity, potentially leading to communication failures, dropped connections, or complete network service unavailability. The impact is particularly severe in automotive applications where connectivity is critical for safety systems, infotainment, and vehicle-to-everything communications. This vulnerability can be exploited to disrupt network services without requiring privileged access or complex attack vectors, making it particularly dangerous in automotive environments where reliable connectivity is paramount.
The vulnerability affects Qualcomm Snapdragon platforms across multiple product categories including automotive systems, mobile devices, connectivity modules, and compute platforms, indicating a widespread impact across the mobile ecosystem. Attackers could potentially leverage this flaw to create persistent denial of service conditions that would require system reboot or manual intervention to resolve. The flaw also creates potential for more complex attack chains where the incorrect state information could be used to bypass other security mechanisms or create conditions for additional vulnerabilities. This type of vulnerability aligns with ATT&CK technique T1499.001 which describes "Network Denial of Service" and demonstrates how protocol-level flaws can be exploited to create system-level service disruptions. Organizations should implement immediate mitigations including firmware updates from Qualcomm, network monitoring for abnormal connection state patterns, and potential temporary disabling of affected network services until proper patches are deployed. The vulnerability highlights the importance of proper protocol state management and error handling in embedded systems, particularly in automotive applications where safety and reliability are critical requirements.