CVE Vulnerabilities

CVE-2021-3418

Improper Preservation of Permissions

Published: Mar 15, 2021 | Modified: Mar 22, 2021
CVSS 3.x
6.4
MEDIUM
Source:
NVD
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
4.4 MEDIUM
AV:L/AC:M/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
Ubuntu

If certificates that signed grub are installed into db, grub can be booted directly. It will then boot any kernel without signature validation. The booted kernel will think it was booted in secureboot mode and will implement lockdown, yet it could have been tampered. This flaw is a reintroduction of CVE-2020-15705 and only affects grub2 versions prior to 2.06 and upstream and distributions using the shim_lock mechanism.

Weakness

The product does not preserve permissions or incorrectly preserves permissions when copying, restoring, or sharing objects, which can cause them to have less restrictive permissions than intended.

Affected Software

Name Vendor Start Version End Version
Grub2 Gnu * 2.06 (excluding)

References