CVE-2018-18558 : Security Advisory and Response

A vulnerability has been discovered in versions 2.x and 3.x of Espressif ESP-IDF, allowing attackers to execute unauthorized code by bypassing secure boot checks.

Understanding CVE-2018-18558

This CVE identifies a security flaw in the Espressif ESP-IDF bootloader that enables attackers to execute arbitrary code.

What is CVE-2018-18558?

The vulnerability arises from inadequate validation of user input data in the 2nd stage bootloader, allowing attackers to bypass secure boot checks and run unauthorized code.

The Impact of CVE-2018-18558

Attackers in close proximity can exploit the vulnerability to execute unauthorized code
Successful attacks require disabling flash encryption or finding alternative vulnerabilities

Technical Details of CVE-2018-18558

This section provides technical insights into the vulnerability.

Vulnerability Description

The issue stems from insufficient validation of input data in the 2nd stage bootloader, enabling attackers to craft a binary that overwrites a code segment in the bootloader's "process_segment" function.

Affected Systems and Versions

Versions 2.x and 3.x of Espressif ESP-IDF before 3.0.6 and 3.1.1

Exploitation Mechanism

Attackers create a specific application binary to overwrite a code segment in the bootloader
Located in the "esp_image_format.c" file within the "components/bootloader_support/src" directory

Mitigation and Prevention

Protecting systems from CVE-2018-18558 requires immediate actions and long-term security practices.

Immediate Steps to Take

Enable flash encryption to prevent unauthorized code execution
Regularly update the ESP-IDF to the latest secure versions

Long-Term Security Practices

Implement secure coding practices to prevent buffer overflows and code injection
Conduct regular security audits and penetration testing

Patching and Updates

Apply patches provided by Espressif to address the vulnerability