PT-2021-7384 · Grub2+2 · Grub2+2
Marco Benatto
·
Published
2021-03-01
·
Updated
2022-09-20
·
CVE-2021-3418
CVSS v3.1
6.4
Medium
| Vector | AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H |
Name of the Vulnerable Software and Affected Versions
Grub2 versions prior to 2.06
Description
The issue is related to the implementation of the shim lock mechanism in Grub2, which is associated with incorrect cryptographic signature verification. This flaw allows an attacker to boot any kernel without signature validation, potentially leading to tampering. The booted kernel may think it was booted in secure boot mode and implement lockdown, despite the potential tampering. The estimated number of potentially affected devices worldwide is not specified.
Recommendations
For Grub2 versions prior to 2.06, update to version 2.06 or later to resolve the issue.
As a temporary workaround, consider disabling the use of the shim lock mechanism until a patch is available.
Restrict access to the boot process to minimize the risk of exploitation.
Exploit
Fix
Improper Preservation of Permissions
Improper Verification of Cryptographic Signature
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Related Identifiers
Affected Products
Alt Linux
Grub2
Red Os