CVE-2020-11268 in Snapdragon Auto
Summary
by MITRE • 05/07/2021
Potential UE reset while decoding a crafted Sib1 or SIB1 that schedules unsupported SIBs and can lead to denial of service in Snapdragon Auto, Snapdragon Mobile
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Analysis
by VulDB Data Team • 05/12/2021
This vulnerability resides in the Qualcomm Snapdragon automotive and mobile platform ecosystems where the baseband processor handles system information block decoding during cellular network synchronization. The flaw manifests when the processor encounters specially crafted System Information Block 1 messages that reference unsupported or malformed System Information Blocks. The vulnerability stems from inadequate input validation and error handling within the radio access network decoding routines that process these critical signaling messages. When the baseband processor attempts to decode such malformed SIB1 messages, it can trigger an unexpected state transition leading to a complete user equipment reset. This behavior represents a denial of service condition that can occur during normal network access procedures and potentially disrupt cellular connectivity for the affected device.
The technical implementation of this vulnerability exploits a weakness in the protocol stack's handling of system information messages that are part of the LTE and 5G cellular communication standards. The flaw is classified under CWE-129 as insufficient input validation and can be mapped to ATT&CK technique T1499.004 for network denial of service. The specific condition occurs when the processor encounters SIB1 messages that reference SIB types not supported by the current firmware implementation, causing an unhandled exception during the decoding process. This typically happens when the processor's scheduler attempts to allocate resources for processing unsupported SIB types, leading to a memory access violation or state corruption that triggers the system reset mechanism. The vulnerability demonstrates poor error recovery handling where the system fails to gracefully handle malformed signaling rather than rejecting the invalid input and continuing normal operation.
The operational impact of this vulnerability extends beyond simple service disruption as it affects automotive systems that rely on continuous connectivity for safety-critical functions. In Snapdragon Auto platforms, this could potentially compromise vehicle communication systems during critical driving scenarios, while mobile devices may experience unexpected reboots during network handover procedures or when connecting to specific carrier networks. The vulnerability is particularly concerning because it can be triggered remotely through malicious network signaling without requiring physical access to the device, making it a significant threat to both consumer and automotive security. Attackers could potentially exploit this vulnerability to repeatedly disrupt connectivity for targeted devices or to create a persistent denial of service condition that degrades user experience and system reliability.
Mitigation strategies should focus on firmware updates from device manufacturers that implement proper input validation and graceful error handling for malformed signaling messages. Qualcomm has released patches addressing this vulnerability in subsequent firmware versions, requiring device manufacturers to update their implementations. Network operators should also monitor for suspicious signaling patterns that could indicate exploitation attempts. Device security measures include implementing robust input sanitization routines and establishing proper exception handling mechanisms within the baseband processor's signaling decode modules. The vulnerability highlights the importance of comprehensive testing for edge cases in protocol implementations and adherence to secure coding practices that prevent unexpected state transitions during error conditions. Organizations should also consider network-level monitoring solutions that can detect and alert on anomalous signaling patterns that may indicate attempted exploitation of similar vulnerabilities.