CVE-2019-6156 Explained : Impact and Mitigation

Lenovo systems may experience a vulnerability related to BIOS configuration after waking from sleep mode.

Understanding CVE-2019-6156

This CVE involves a misconfiguration issue in the SPI Protected Range Registers (PRx) of certain BIOS versions for Lenovo systems.

What is CVE-2019-6156?

Lenovo systems utilize SMM BIOS Write Protection to prevent writing actions on SPI Flash. However, a misconfiguration in PRx after waking from S3 sleep mode poses a security risk.

The Impact of CVE-2019-6156

The misconfiguration does not affect the functionality of SMM BIOS Write Protection but leaves systems vulnerable to unauthorized writing actions on SPI Flash.

Technical Details of CVE-2019-6156

This section provides in-depth technical insights into the vulnerability.

Vulnerability Description

After waking from S3 sleep mode, certain versions of Lenovo BIOS fail to properly configure the SPI Protected Range Registers (PRx), potentially exposing systems to unauthorized writing actions.

Affected Systems and Versions

Product: BIOS
Vendor: Lenovo
Affected Versions: Various

Exploitation Mechanism

The vulnerability occurs due to a misconfiguration in the PRx settings after the system resumes from S3 sleep mode.

Mitigation and Prevention

Protecting systems from CVE-2019-6156 requires immediate actions and long-term security practices.

Immediate Steps to Take

Regularly check for BIOS updates from Lenovo to address the misconfiguration issue.
Avoid leaving systems unattended in sleep mode for extended periods.

Long-Term Security Practices

Implement a robust system monitoring and intrusion detection system to detect unauthorized changes.
Educate users on the importance of system security and the risks associated with unauthorized BIOS modifications.

Patching and Updates

Lenovo has released BIOS updates for affected systems to properly configure the PRx and mitigate the vulnerability.