How To Fix The Three Buffer Overflow Vulnerabilities In Lenovo BIOS

Martin Smolár, a security researcher from ESET, has disclosed 3 buffer overflow vulnerabilities in Lenovo BIOS. The vulnerability is impacting multiple Lenovo Notebook devices including several ThinkBook models leaving millions of laptops vulnerable. These vulnerabilities enable advisories to hijack the OS execution flow and disable some important security features on the affected devices. This helps threat actors to achieve arbitrary code execution in the early phases of the platform boot. It is highly important for all the Lenovo Laptop holders to be aware of these three buffer overflow vulnerabilities. We created this post that tells how to fix these three buffer overflow vulnerabilities in Lenovo BIOS.

The vendor has published advisory for the second time since the beginning of the year. The first set of three vulnerabilities Lenovo fixed are CVE-2021-3970, CVE-2021-3971, and CVE-2021-3972, vulnerabilities enable advisories to deploy and execute malicious firmware on the affected devices.

A Small Note On UEFI vs BIOS:

Sometimes, you may get confused between UEFI and BIOS. Here is a small note that lets you know the difference between UEFI and BIOS in simple words.

UEFI stands for Unified Extensible Firmware Interface and is essentially a software program that sits on top of your computer’s hardware and provides an interface between the operating system and the hardware. UEFI is the successor to BIOS, offering a more modern interface as well as additional features and capabilities.

BIOS, on the other hand, stands for Basic Input/Output System. It is a ROM chip that stores information about your computer’s hardware and how it should be configured. The BIOS is responsible for booting up your computer, and it generally does not offer as many features or capabilities as UEFI.

So, UEFI is a more modern version of BIOS that offers additional features and capabilities. It is not required on all computers, but it is becoming more common. If your computer has UEFI, you will likely see a UEFI options menu when you boot up the computer that will allow you to change UEFI settings.

The Three Buffer Overflow Vulnerabilities In Lenovo BIOS:

On July 13, 2022, Martin Smolár, a security researcher from ESET tweeted about the three flaws to the PC manufacturer. The following is a summary of the three buffer overflow vulnerabilities as outlined by Lenovo.

CVE-2022-1890: This is a buffer overflow vulnerability in the ReadyBootDxe driver in some Lenovo notebook models which would allow an attacker with local privileges to execute arbitrary code on the affected devices. The flaw is due to an insufficient validation of an NVRAM variable called “DataSize” in the ReadyBootDxe driver resulting in a buffer overflow.

CVE-2022-1891: This is a buffer overflow vulnerability in the SystemLoadDefaultDxe driver in some Lenovo notebook models which would allow an attacker with local privileges to execute arbitrary code on the affected devices. The flaw is due to an insufficient validation of an NVRAM variable called “DataSize” in the SystemLoadDefaultDxe driver resulting in a buffer overflow.

CVE-2022-1892: This is a buffer overflow vulnerability in the SystemBootManagerDxe driver in some Lenovo notebook models which would allow an attacker with local privileges to execute arbitrary code on the affected devices. The flaw is due to an insufficient validation of an NVRAM variable called “DataSize” in the SystemBootManagerDxe driver resulting in a buffer overflow.

How To Fix The Three Buffer Overflow Vulnerabilities In Lenovo BIOS?

Upgrading the BIOS firmware is the best way to fix these new vulnerabilities in Lenovo Laptops.BIOS can be updated in three different ways in Lenovo Laptops.

Automatic Updates

WinFlash

Update BIOS from Windows

Method 1: Automatic Update

Update Lenovo drivers, BIOS, and applications using Lenovo System Update. Lenovo System Update is the latest program that can be used to update your Lenovo laptop drivers and other software. It can also detect when there are new versions of the BIOS and automatically install them.

To check if your Lenovo laptop has this feature, go to Start Menu > Control Panel > System and Security. Click on “System” and then click on “Advanced system settings.” On the left panel, click on “Advanced” and then click on “Update BIOS.”

If you see the “Update BIOS” option, your Lenovo laptop has the Lenovo System Update feature. If you don’t see this option, your Laptop doesn’t have this feature, and you’ll need to install the BIOS updates manually.

Method 2: WinFlash

Method 3: Update BIOS From Windows

Updating BIOS from Windows is simple and straight. Steps to update system BIOS in Lenovo Laptops:

These are the steps to update the system BIOS in Lenovo Laptops. Following these steps should help you update your BIOS successfully. In case you face any issues, please reach out to the Lenovo support team for assistance.

List Of Lenovo Laptops Vulnerable To CVE-2022-1890, CVE-2022-1891, And CVE-2022-1892:

Lenovo has verified its Laptop modules and published the vulnerable models in its advisory report. Please don’t miss seeing the list from here. Click here for a complete list of all Lenovo Product Security Advisories.

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