CVE-2019-15894 : Exploit Details and Defense Strategies
Learn about CVE-2019-15894, a critical vulnerability in Espressif ESP-IDF versions 2.x, 3.0.x through 3.3.1. Understand the impact, affected systems, exploitation mechanism, and mitigation steps.
A vulnerability has been identified in Espressif ESP-IDF versions 2.x, 3.0.x through 3.0.9, 3.1.x through 3.1.6, 3.2.x through 3.2.3, and 3.3.x through 3.3.1. This vulnerability allows an attacker to bypass Secure Boot digest verification by physically disrupting the ESP32 CPU, leading to the execution of unverified code from flash memory.
Understanding CVE-2019-15894
This CVE highlights a critical security issue in Espressif ESP-IDF versions that can be exploited through fault injection to compromise the boot process of the ESP32 CPU.
What is CVE-2019-15894?
The vulnerability in CVE-2019-15894 enables an attacker to bypass Secure Boot digest verification by physically disrupting the ESP32 CPU, allowing the execution of unverified code from flash memory.
The Impact of CVE-2019-15894
- Successful exploitation can lead to the execution of arbitrary code on affected devices.
- Devices without Flash Encryption enabled are particularly vulnerable to this attack.
Technical Details of CVE-2019-15894
Espressif ESP-IDF versions 2.x, 3.0.x through 3.0.9, 3.1.x through 3.1.6, 3.2.x through 3.2.3, and 3.3.x through 3.3.1 are affected by this vulnerability.
Vulnerability Description
- Attacker can bypass Secure Boot digest verification by physically disrupting the ESP32 CPU.
- Unverified code from flash memory can be executed as a result of the attack.
Affected Systems and Versions
- Espressif ESP-IDF versions 2.x, 3.0.x through 3.0.9, 3.1.x through 3.1.6, 3.2.x through 3.2.3, and 3.3.x through 3.3.1.
Exploitation Mechanism
- Fault injection is used to disrupt the ESP32 CPU physically.
- Successful fault injection allows the attacker to bypass Secure Boot digest verification.
Mitigation and Prevention
It is crucial to take immediate steps to mitigate the risks posed by CVE-2019-15894.
Immediate Steps to Take
- Implement a firmware modification to permanently enable Flash Encryption if not already enabled.
- Ensure devices are configured with the recommended combination of Secure Boot and Flash Encryption.
Long-Term Security Practices
- Regularly update firmware to address security vulnerabilities.
- Conduct security assessments to identify and address potential weaknesses.
Patching and Updates
- Stay informed about security advisories and updates from Espressif.
- Apply patches promptly to protect against known vulnerabilities.