CVE-2020-14372
Published: 02 March 2021
A flaw was found in grub2 in versions prior to 2.06, where it incorrectly enables the usage of the ACPI command when Secure Boot is enabled. This flaw allows an attacker with privileged access to craft a Secondary System Description Table (SSDT) containing code to overwrite the Linux kernel lockdown variable content directly into memory. The table is further loaded and executed by the kernel, defeating its Secure Boot lockdown and allowing the attacker to load unsigned code. The highest threat from this vulnerability is to data confidentiality and integrity, as well as system availability.
From the Ubuntu security team
Máté Kukri discovered that the acpi command in GRUB 2 allowed privileged users to load crafted ACPI tables when secure boot is enabled. An attacker could use this to bypass UEFI Secure Boot restrictions.
Medium
CVSS 3 base score: 7.5
Status
| Package | Release | Status |
|---|---|---|
|
grub2-signed Launchpad, Ubuntu, Debian |
Upstream |
Needs triage
|
| Ubuntu 21.04 (Hirsute Hippo) |
Released
(1.164)
|
|
| Ubuntu 20.04 LTS (Focal Fossa) |
Released
(1.167.2)
|
|
| Ubuntu 18.04 LTS (Bionic Beaver) |
Released
(1.167~18.04.5)
|
|
| Ubuntu 16.04 ESM (Xenial Xerus) |
Pending
(1.164)
|
|
| Ubuntu 14.04 ESM (Trusty Tahr) |
Needs triage
|
|
|
grub2-unsigned Launchpad, Ubuntu, Debian |
Upstream |
Needs triage
|
| Ubuntu 21.04 (Hirsute Hippo) |
Released
(2.04-1ubuntu42)
|
|
| Ubuntu 20.04 LTS (Focal Fossa) |
Released
(2.04-1ubuntu44.2)
|
|
| Ubuntu 18.04 LTS (Bionic Beaver) |
Released
(2.04-1ubuntu44.1.2)
|
|
| Ubuntu 16.04 ESM (Xenial Xerus) |
Pending
(2.04-1ubuntu42)
|
|
| Ubuntu 14.04 ESM (Trusty Tahr) |
Needs triage
|