CVE-2020-15531 in Bluetooth Low Energy SDK
Summary
by MITRE
Silicon Labs Bluetooth Low Energy SDK before 2.13.3 has a buffer overflow via packet data. This is an over-the-air remote code execution vulnerability in Bluetooth LE in EFR32 SoCs and associated modules running Bluetooth SDK, supporting Central or Observer roles.
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Analysis
by VulDB Data Team • 08/20/2020
The vulnerability identified as CVE-2020-15531 represents a critical buffer overflow flaw within Silicon Labs Bluetooth Low Energy SDK versions prior to 2.13.3. This vulnerability specifically affects EFR32 System-on-Chips and their associated modules that operate using Bluetooth SDK protocols, creating a significant security risk for devices utilizing these components. The flaw manifests when processing packet data received over Bluetooth Low Energy connections, where malformed or specially crafted data packets can trigger memory corruption within the device's processing stack. The vulnerability is particularly concerning because it enables over-the-air remote code execution, meaning attackers can exploit this flaw without physical access to the target device, simply by transmitting malicious Bluetooth packets within range of affected equipment.
The technical nature of this vulnerability stems from inadequate input validation and memory management within the Bluetooth LE stack implementation. When devices operating in Central or Observer roles receive packet data, the SDK fails to properly validate the size and structure of incoming data before copying it into fixed-size buffers. This classic buffer overflow condition allows attackers to overwrite adjacent memory locations, potentially corrupting program execution flow or injecting malicious code. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which occurs when data is copied into a buffer without proper bounds checking. The impact is amplified by the fact that affected devices typically operate continuously in wireless environments, making them susceptible to persistent exploitation attempts from nearby attackers.
Operationally, this vulnerability presents severe consequences for any organization deploying EFR32-based Bluetooth Low Energy devices, particularly in industrial IoT, healthcare, automotive, and smart building applications. The remote code execution capability means that adversaries can potentially take complete control of affected devices, access sensitive data, or use them as entry points for broader network infiltration. The vulnerability affects devices that maintain Bluetooth LE connections in Central or Observer modes, which includes a wide range of wireless sensors, actuators, and communication modules commonly deployed in enterprise and industrial environments. The over-the-air exploitation capability makes this vulnerability particularly dangerous as it can be leveraged from considerable distances without requiring physical proximity to the target device, potentially allowing attackers to compromise large deployments from a single location.
Mitigation strategies for CVE-2020-15531 must prioritize immediate firmware updates to versions 2.13.3 or later, which contain the necessary patches to address the buffer overflow condition. Organizations should conduct comprehensive inventories of all EFR32-based devices within their networks to identify affected systems and prioritize remediation efforts based on risk assessment. Network segmentation and monitoring solutions should be implemented to detect anomalous Bluetooth traffic patterns that might indicate exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1059.007 for remote code execution and T1566 for credential access through wireless communications, making it a critical target for defensive security operations. Additional defensive measures include implementing Bluetooth Low Energy access controls, disabling unnecessary Bluetooth functionality, and establishing robust network monitoring to detect and respond to potential exploitation attempts. Organizations should also consider the broader implications of this vulnerability within their overall security posture, as compromised Bluetooth devices can serve as stepping stones for more extensive network breaches.