Lenovo laptops - UEFI vulnerabilities

FanJ · Apr 19, 2022

When “secure” isn’t secure at all: High‑impact UEFI vulnerabilities discovered in Lenovo consumer laptops
ESET - 19 april 2022
https://www.welivesecurity.com/2022...uefi-vulnerabilities-lenovo-consumer-laptops/

ESET researchers have discovered and analyzed three vulnerabilities affecting various Lenovo consumer laptop models. The first two of these vulnerabilities – CVE-2021-3971, CVE-2021-3972 – affect UEFI firmware drivers originally meant to be used only during the manufacturing process of Lenovo consumer notebooks. Unfortunately, they were mistakenly included also in the production BIOS images without being properly deactivated. These affected firmware drivers can be activated by attacker to directly disable SPI flash protections (BIOS Control Register bits and Protected Range registers) or the UEFI Secure Boot feature from a privileged user-mode process during OS runtime. It means that exploitation of these vulnerabilities would allow attackers to deploy and successfully execute SPI flash or ESP implants, like LoJax or our latest UEFI malware discovery ESPecter, on the affected devices.
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Lenovo:
Lenovo Notebook BIOS Vulnerabilities
Last Modified Date:04/18/2022
https://support.lenovo.com/nl/en/product_security/len-73440

Summary Description:

The following vulnerabilities were reported in Lenovo Notebook BIOS.

CVE-2021-3970: A potential vulnerability in LenovoVariable SMI Handler due to insufficient validation in some Lenovo Notebook models may allow an attacker with local access and elevated privileges to execute arbitrary code.

CVE-2021-3971: A potential vulnerability by a driver used during older manufacturing processes on some consumer Lenovo Notebook devices that was mistakenly included in the BIOS image could allow an attacker with elevated privileges to modify firmware protection region by modifying an NVRAM variable.

CVE-2021-3972: A potential vulnerability by a driver used during manufacturing process on some consumer Lenovo Notebook devices that was mistakenly not deactivated may allow an attacker with elevated privileges to modify secure boot setting by modifying an NVRAM variable.
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Read more at those links.

FanJ · Apr 20, 2022

Article at Bleeping Computer - 19 April 2022
Lenovo UEFI firmware driver bugs affect over 100 laptop models
https://www.bleepingcomputer.com/ne...re-driver-bugs-affect-over-100-laptop-models/

Lenovo has published a security advisory on vulnerabilities that impact its Unified Extensible Firmware Interface (UEFI) loaded on at least 100 of its laptop models.
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All three vulnerabilities were discovered by ESET researchers and reported responsibly to Lenovo in October last year. They affect more than 100 consumer laptop models, including IdeaPad 3, Legion 5 Pro-16ACH6 H, and Yoga Slim 9-14ITL05, which likely translates to millions of users with vulnerable devices.
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ESET has provided a detailed technical analysis of the three vulnerabilities uncovered noting that “UEFI threats can be extremely stealthy and dangerous” because they execute “early in the boot process, before transferring control to the operating system.”
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Read more there.

FanJ · Jul 15, 2022

Recently both BleepingComputer and BornCity had articles about Lenovo UEFI vulnerabilities but it is not clear to me whether those are the same as mentioned in the above two postings from April 2022.

BleepingComputer - 13 July 2022
New UEFI firmware flaws impact over 70 Lenovo laptop models
https://www.bleepingcomputer.com/ne...re-flaws-impact-over-70-lenovo-laptop-models/

Borncity - 14 July 2022
UEFI firmware bug compromises over 70 Lenovo notebooks (July 2022)
https://borncity.com/win/2022/07/14/uefi-firmware-bug-gefhrdet-ber-70-lenovo-notebooks-juli-2022/

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Lenovo laptops - UEFI vulnerabilities

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