CVE-2022-46401 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) accepts PauseEncReqPlainText before pairing is complete.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 01/21/2023
The Microchip RN4870 module firmware version 1.43 contains a critical security vulnerability that allows unauthorized access to the Bluetooth Low Energy communication channel before the pairing process is completed. This vulnerability affects both the firmware itself and the associated PIC LightBlue Explorer Demo software version 4.2 DT100112. The flaw resides in the firmware's handling of the PauseEncReqPlainText command which should only be processed after successful device pairing has been established.
This vulnerability represents a significant breakdown in the Bluetooth security model where encryption parameters are being accepted and processed prematurely within the pairing sequence. The technical implementation allows an attacker to send a PauseEncReqPlainText command to the device before the pairing authentication has been fully completed, potentially enabling man-in-the-middle attacks or unauthorized modification of the encryption keys during the pairing process. The vulnerability stems from inadequate validation of the pairing state before accepting encryption-related commands, creating a window of opportunity for malicious actors to interfere with the secure connection establishment.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential data interception and modification capabilities. Attackers can exploit this weakness to gain access to sensitive information transmitted over the Bluetooth channel, potentially compromising the confidentiality and integrity of communications between paired devices. The vulnerability affects all devices running the affected firmware version, making it particularly concerning for IoT deployments where multiple devices may be communicating over Bluetooth with the same vulnerable module. This flaw can lead to complete compromise of the Bluetooth communication security model, undermining the fundamental assumptions of secure pairing and encryption in Bluetooth Low Energy implementations.
Security mitigations for this vulnerability require immediate firmware updates from Microchip to address the improper command handling during the pairing process. Organizations should implement network segmentation to limit exposure of affected devices and monitor for suspicious Bluetooth activity. The vulnerability aligns with CWE-312 (Sensitive Data Exposure) and CWE-310 (Cryptographic Issues) classifications, while also mapping to ATT&CK technique T1566 (Phishing) and T1071.001 (Application Layer Protocol: Web Protocols) when considering the broader attack surface. Additionally, security professionals should consider implementing device authentication mechanisms and regular security assessments to detect similar issues in other Bluetooth implementations. The vulnerability highlights the critical importance of proper state validation in embedded systems and demonstrates how seemingly minor implementation flaws can create significant security risks in wireless communication protocols.