CVE-2022-45191 in RN4870
Summary
by MITRE • 02/08/2023
An issue was discovered on Microchip RN4870 1.43 devices. An attacker within BLE radio range can cause a denial of service by sending a pair confirm message with wrong values.
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Analysis
by VulDB Data Team • 03/06/2023
The vulnerability identified as CVE-2022-45191 affects Microchip RN4870 Bluetooth Low Energy devices running firmware version 1.43 and potentially earlier versions. This issue represents a denial of service condition that can be exploited by adversaries within the Bluetooth radio range of affected devices. The vulnerability stems from insufficient input validation during the Bluetooth pairing process, specifically when handling pair confirm messages. These messages are part of the Bluetooth security protocol used to authenticate connections between devices and ensure the integrity of the pairing procedure.
The technical flaw manifests when an attacker crafts and transmits a malformed pair confirm message containing incorrect values to the target device. This manipulation occurs during the Bluetooth pairing process where devices exchange confirm values to verify that both parties possess the correct pairing key. The RN4870 device fails to properly validate these incoming confirm values, leading to a system crash or lockup that results in the device becoming unresponsive. This behavior aligns with CWE-248, which addresses improper exception handling, and represents a classic example of a resource exhaustion or system stability attack that can be executed remotely within the Bluetooth communication range.
The operational impact of this vulnerability extends beyond simple service disruption, as it can effectively render the affected Bluetooth device unusable for legitimate communication purposes. When exploited successfully, the denial of service condition prevents authorized users from establishing normal Bluetooth connections to the device, potentially disrupting critical applications such as medical devices, industrial sensors, or consumer electronics that rely on stable Bluetooth connectivity. The vulnerability is particularly concerning in environments where Bluetooth devices are deployed in critical infrastructure or safety-sensitive applications where unexpected service interruption could have serious consequences. This type of attack falls under the ATT&CK technique T1499.004, which describes network denial of service attacks specifically targeting communication protocols.
Mitigation strategies for this vulnerability should focus on both immediate protective measures and long-term firmware updates. Organizations should prioritize updating affected RN4870 devices to the latest firmware versions that address this specific validation issue. Until such updates are available, network administrators should implement physical security controls to limit unauthorized access to the Bluetooth radio range of affected devices, as the vulnerability requires proximity to the target device for exploitation. Additional protective measures include monitoring Bluetooth pairing attempts for unusual patterns and implementing network segmentation to isolate critical Bluetooth devices from general network access. Security teams should also consider deploying Bluetooth monitoring tools that can detect anomalous pairing behavior and alert administrators to potential exploitation attempts. The vulnerability highlights the importance of robust input validation in embedded systems and demonstrates how seemingly minor protocol implementation flaws can result in significant operational disruptions.