CVE-2021-28139 : Exploit Details and Defense Strategies

The Bluetooth Classic implementation in Espressif ESP-IDF 4.4 and earlier is vulnerable to CVE-2021-28139, which allows attackers in radio range to trigger arbitrary code execution in ESP32. Here's a detailed overview of this critical vulnerability.

Understanding CVE-2021-28139

This section provides insights into the nature of the CVE-2021-28139 vulnerability.

What is CVE-2021-28139?

The Bluetooth Classic implementation in Espressif ESP-IDF 4.4 and earlier fails to restrict the Feature Page, enabling attackers within radio range to execute arbitrary code on ESP32 devices using a specially crafted payload.

The Impact of CVE-2021-28139

CVE-2021-28139 poses a severe threat as it allows remote attackers to exploit ESP32 devices, compromising their security and enabling unauthorized code execution.

Technical Details of CVE-2021-28139

This section delves into the technical aspects of CVE-2021-28139.

Vulnerability Description

The vulnerability arises from inadequate validation of the Feature Page in Espressif ESP-IDF 4.4 and earlier, allowing malicious actors to leverage an LMP Feature Response Extended packet to execute arbitrary code via a manipulated bitfield payload.

Affected Systems and Versions

Espressif ESP-IDF 4.4 and earlier versions are impacted by this vulnerability, potentially affecting a wide range of ESP32 devices.

Exploitation Mechanism

By sending a specifically crafted Extended Features bitfield payload, threat actors within radio proximity can exploit this vulnerability to trigger arbitrary code execution on vulnerable ESP32 devices.

Mitigation and Prevention

In this section, we discuss the steps to mitigate and prevent the exploitation of CVE-2021-28139.

Immediate Steps to Take

Users are advised to apply patches and updates provided by Espressif to address the CVE-2021-28139 vulnerability promptly.

Long-Term Security Practices

Implementing network segmentation, maintaining updated firmware, and monitoring Bluetooth activity can enhance the long-term security posture against such vulnerabilities.

Patching and Updates

Regularly check for security advisories from Espressif and apply patches as soon as they are released to protect ESP32 devices from potential exploitation.