CVE-2021-28136 Explained : Impact and Mitigation

The CVE-2021-28136 vulnerability affects the Bluetooth Classic implementation in Espressif ESP-IDF 4.4 and earlier versions. Attackers can exploit this vulnerability to trigger memory corruption and potentially crash ESP32 devices by replaying LMP packets.

Understanding CVE-2021-28136

This section provides insights into the nature and impact of the CVE-2021-28136 vulnerability.

What is CVE-2021-28136?

The vulnerability arises from the improper handling of multiple LMP IO Capability Request packets during the pairing process in the Bluetooth Classic implementation of Espressif ESP-IDF, leading to memory corruption and potential device crashes.

The Impact of CVE-2021-28136

Attackers within radio range can exploit CVE-2021-28136 to induce memory corruption and execute a denial-of-service attack by sending duplicated LMP packets, potentially disrupting the target device's operations.

Technical Details of CVE-2021-28136

This section delves into the specific technical aspects of the CVE-2021-28136 vulnerability.

Vulnerability Description

The vulnerability in Espressif ESP-IDF allows attackers in radio range to manipulate the Bluetooth Classic pairing process, triggering memory corruption and causing the ESP32 device to crash via replayed LMP packets.

Affected Systems and Versions

Espressif ESP-IDF 4.4 and earlier versions are affected by this vulnerability, impacting devices that utilize these Bluetooth Classic implementations.

Exploitation Mechanism

By sending multiple LMP IO Capability Request packets within radio range, attackers can exploit the flaw to corrupt memory and potentially crash ESP32 devices using the vulnerable Bluetooth Classic implementation.

Mitigation and Prevention

This section outlines strategies to mitigate and prevent the exploitation of CVE-2021-28136.

Immediate Steps to Take

To mitigate the risk associated with CVE-2021-28136, users are advised to apply security patches and updates released by Espressif to address the vulnerability promptly.

Long-Term Security Practices

Establishing robust security protocols and conducting regular security assessments can bolster the overall security posture of IoT devices, reducing the likelihood of successful attacks exploiting Bluetooth vulnerabilities.

Patching and Updates

Regularly updating the ESP-IDF software and implementing patches provided by Espressif for identified security vulnerabilities is crucial to maintaining the security and integrity of ESP32 devices.