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cve[email protected]CVE-2021-3418
HistoryMar 15, 2021 - 10:15 p.m.

CVE-2021-3418

2021-03-1522:15:00
CWE-281
web.nvd.nist.gov
109
3
cve-2021-3418
grub2
certificate validation
secureboot
tampered kernel
nvd

6.4 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

HIGH

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

6.8 Medium

AI Score

Confidence

High

4.4 Medium

CVSS2

Access Vector

LOCAL

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:L/AC:M/Au:N/C:P/I:P/A:P

0.0004 Low

EPSS

Percentile

11.7%

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.

VendorProductVersionCPE
gnugrub2*cpe:2.3:a:gnu:grub2:*:*:*:*:*:*:*:*

Social References

More

6.4 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

HIGH

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

6.8 Medium

AI Score

Confidence

High

4.4 Medium

CVSS2

Access Vector

LOCAL

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:L/AC:M/Au:N/C:P/I:P/A:P

0.0004 Low

EPSS

Percentile

11.7%