CVE-2021-3971 Explained : Impact and Mitigation
Learn about CVE-2021-3971, a medium-severity vulnerability in Lenovo Notebook BIOS allowing attackers to modify firmware protection regions. Find mitigation steps here.
A driver used during older manufacturing processes on some consumer Lenovo Notebook devices that was mistakenly included in the BIOS image has a potential vulnerability. This flaw could allow an attacker with elevated privileges to modify firmware protection region by changing an NVRAM variable.
Understanding CVE-2021-3971
This section provides insights into the nature and impact of CVE-2021-3971.
What is CVE-2021-3971?
CVE-2021-3971 is a vulnerability found in certain Lenovo Notebook BIOS images that enables attackers with elevated privileges to tamper with the firmware protection region by manipulating an NVRAM variable.
The Impact of CVE-2021-3971
The vulnerability poses a medium threat with a base severity score of 6.7. It has a low attack complexity and vector, but high impacts on confidentiality, integrity, and system availability. Attackers with elevated privileges can exploit this flaw to make unauthorized modifications to the firmware protection region.
Technical Details of CVE-2021-3971
This section delves into the specific technical aspects of CVE-2021-3971.
Vulnerability Description
The vulnerability arises from a driver used during older manufacturing processes in Lenovo Notebook devices. When mistakenly included in the BIOS image, it allows the modification of firmware protection regions by altering an NVRAM variable.
Affected Systems and Versions
The vulnerability impacts various versions of Lenovo Notebook BIOS images resulting from older manufacturing processes.
Exploitation Mechanism
Attackers with elevated privileges can exploit this vulnerability by manipulating the NVRAM variable in the BIOS image to modify the firmware protection region.
Mitigation and Prevention
This section outlines the steps to mitigate and prevent the exploitation of CVE-2021-3971.
Immediate Steps to Take
Users are advised to update their system firmware to the recommended version mentioned in the Product Impact section of LEN-73440 or newer.
Long-Term Security Practices
In the long term, it is crucial to regularly update system firmware and BIOS to address known vulnerabilities and enhance overall security.
Patching and Updates
Lenovo recommends applying patches and updates promptly to protect Lenovo Notebook devices from potential exploitation of CVE-2021-3971.