CVE-2022-46400 in RN4870
Summary
by MITRE • 12/20/2022
The Microchip RN4870 module firmware 1.43 (and the Microchip PIC LightBlue Explorer Demo 4.2 DT100112) allows attackers to bypass passkey entry in legacy pairing.
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Analysis
by VulDB Data Team • 01/21/2023
The Microchip RN4870 module firmware version 1.43 contains a critical security flaw that undermines the integrity of legacy Bluetooth pairing mechanisms. This vulnerability affects not only the standalone firmware but also the Microchip PIC LightBlue Explorer Demo version 4.2 DT100112, indicating a widespread impact across related products. The issue resides in the passkey entry validation process during Bluetooth legacy pairing procedures, where attackers can exploit a weakness to circumvent the expected authentication flow.
The technical flaw manifests as a failure in proper passkey validation within the Bluetooth pairing protocol implementation. During legacy pairing, devices typically require users to enter a passkey to establish trust between communicating parties. The vulnerability allows unauthorized parties to bypass this critical security check, effectively enabling man-in-the-middle attacks or unauthorized device access. This weakness operates at the protocol level where the firmware fails to properly validate the passkey entered during the pairing process, potentially allowing attackers to establish connections without proper authentication.
The operational impact of this vulnerability is significant for any system utilizing the affected Microchip modules. Organizations deploying devices with RN4870 firmware may experience unauthorized access to sensitive data, potential data interception, and compromise of connected networks. The vulnerability affects the fundamental security model of Bluetooth legacy pairing, which is still widely used in industrial IoT applications, medical devices, and automotive systems where these modules are prevalent. Attackers can exploit this weakness to gain access to protected networks, steal sensitive information, or potentially manipulate connected devices without detection.
Security professionals should consider this vulnerability in the context of CWE-312, which addresses the exposure of sensitive information through improper handling of authentication data. The flaw also aligns with ATT&CK techniques related to credential access and initial access through network protocols. Mitigation strategies include immediate firmware updates to versions that address the passkey validation issue, implementation of additional network segmentation controls, and deployment of monitoring solutions to detect unauthorized pairing attempts. Organizations should also conduct thorough inventory assessments to identify all affected devices and implement temporary security controls such as disabling legacy pairing modes where possible. The vulnerability underscores the importance of proper authentication protocol implementation and highlights the need for continuous security testing of embedded firmware components in IoT environments.