UEFI variable unlocking via hard-coded SMI credential
Published Aug 23, 2023 · Updated Aug 3, 2024
Use of a hard-coded credential in LCFC BIOS for Lenovo Notebook models allows local users with elevated privileges to unlock UEFI variables. The SMI handler accepts a credential embedded in firmware instead of validating a caller-specific secret before releasing the UEFI-variable lock. Administrative local access is required; Lenovo has not disclosed which variables become writable or the resulting configuration changes.
Summary
What happened
Use of a hard-coded credential in LCFC BIOS for Lenovo Notebook models allows local users with elevated privileges to unlock UEFI variables. The SMI handler accepts a credential embedded in firmware instead of validating a caller-specific secret before releasing the UEFI-variable lock. Administrative local access is required; Lenovo has not disclosed which variables become writable or the resulting configuration changes.
The record
- CVE
- CVE-2022-3744
- Published
- Aug 23, 2023
- Updated
- Aug 3, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-798
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Aug 23, 2023CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
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Attacks
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