CVE-2021-3418

Published: 02 March 2021

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.

Priority

Medium

CVSS 3 base score: 6.4

Status

Package Release Status
grub2
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo) Not vulnerable

Ubuntu 20.10 (Groovy Gorilla) Not vulnerable

Ubuntu 20.04 LTS (Focal Fossa) Not vulnerable

Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable

Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable

Ubuntu 14.04 ESM (Trusty Tahr) Not vulnerable

grub2-signed
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo) Not vulnerable

Ubuntu 20.10 (Groovy Gorilla) Not vulnerable

Ubuntu 20.04 LTS (Focal Fossa) Not vulnerable

Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable

Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable

Ubuntu 14.04 ESM (Trusty Tahr) Not vulnerable

grub2-unsigned
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo) Not vulnerable

Ubuntu 20.10 (Groovy Gorilla) Not vulnerable

Ubuntu 20.04 LTS (Focal Fossa) Not vulnerable

Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable

Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable

Ubuntu 14.04 ESM (Trusty Tahr) Not vulnerable

Notes

AuthorNote
sbeattie
does not affect grub2 as packaged in Ubuntu, we already had
to address CVE-2020-15705.
sbeattie
grub2-unsigned will contain fixes and supersede grub2, which will contain only BIOS grub bits.

References