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CVE-2018-18653

Published: 25 October 2018

The Linux kernel, as used in Ubuntu 18.10 and when booted with UEFI Secure Boot enabled, allows privileged local users to bypass intended Secure Boot restrictions and execute untrusted code by loading arbitrary kernel modules. This occurs because a modified kernel/module.c, in conjunction with certain configuration options, leads to mishandling of the result of signature verification.

From the Ubuntu Security Team

Daniel Dadap discovered that the module loading implementation in the Linux kernel did not properly enforce signed module loading when booted with UEFI Secure Boot in some situations. A local privileged attacker could use this to execute untrusted code in the kernel.

Notes

AuthorNote
sbeattie
from the commit addressing the issue:
Recent versions of the "secure boot lockdown" patches introduced
support for using IMA signatures for module signing instead of
the standard mechanism. This was causing issues and was removed,
but the code was missed which actually defers the verification to
IMA when IMA enforcement is enabled. With our config this means
that by default module signatures are not being enforced under
kernel lockdown.
Priority

Medium

CVSS 3 base score: 7.8

Status

Package Release Status
linux
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.13.0-16.19)
cosmic
Released (4.18.0-12.13)
precise Ignored
(was needs-triage ESM criteria)
trusty Not vulnerable
(3.11.0-12.19)
upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.2.0-16.19)
Patches:
Introduced by

local-2018-18653-break

Fixed by local-2018-18653-fix
linux-aws
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.15.0-1001.1)
cosmic
Released (4.18.0-1006.7)
precise Does not exist

trusty Not vulnerable
(4.4.0-1002.2)
upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.4.0-1001.10)
linux-aws-hwe
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.15.0-1030.31~16.04.1)
linux-azure
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.15.0-1002.2)
cosmic
Released (4.18.0-1006.6)
precise Does not exist

trusty Not vulnerable
(4.15.0-1023.24~14.04.1)
upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.11.0-1009.9)
linux-azure-edge
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.18.0-1006.6~18.04.1)
cosmic Does not exist

precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.13.0-1003.3)
linux-euclid
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Ignored
(was needs-triage ESM criteria)
linux-flo
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist
(trusty was ignored [abandoned])
upstream
Released (2.6.12~rc2)
xenial Ignored
(abandoned)
linux-gcp
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.15.0-1001.1)
cosmic
Released (4.18.0-1004.5)
precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.10.0-1004.4)
linux-gcp-edge
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.18.0-1004.5~18.04.1)
cosmic Does not exist

precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Does not exist

linux-gke
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Ignored
(end-of-life)
linux-goldfish
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist
(trusty was ignored [abandoned])
upstream
Released (2.6.12~rc2)
xenial Ignored
(end-of-life)
linux-grouper
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist
(trusty was ignored [abandoned])
upstream
Released (2.6.12~rc2)
xenial Does not exist

linux-hwe
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.18.0-13.14~18.04.1)
cosmic Does not exist

precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.8.0-36.36~16.04.1)
linux-hwe-edge
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.18.0-13.14~18.04.1)
cosmic Does not exist

precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.8.0-36.36~16.04.1)
linux-kvm
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.15.0-1002.2)
cosmic
Released (4.18.0-1005.5)
precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.4.0-1004.9)
linux-lts-trusty
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Ignored
(was needs-triage ESM criteria)
trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Does not exist

linux-lts-utopic
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist
(trusty was ignored [out of standard support])
upstream
Released (2.6.12~rc2)
xenial Does not exist

linux-lts-vivid
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist
(trusty was ignored [out of standard support])
upstream
Released (2.6.12~rc2)
xenial Does not exist

linux-lts-wily
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist
(trusty was ignored [out of standard support])
upstream
Released (2.6.12~rc2)
xenial Does not exist

linux-lts-xenial
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Not vulnerable
(4.4.0-13.29~14.04.1)
upstream
Released (2.6.12~rc2)
xenial Does not exist

linux-maguro
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist
(trusty was ignored [abandoned])
upstream
Released (2.6.12~rc2)
xenial Does not exist

linux-mako
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist
(trusty was ignored [abandoned])
upstream
Released (2.6.12~rc2)
xenial Ignored
(abandoned)
linux-manta
Launchpad, Ubuntu, Debian
bionic Does not exist

cosmic Does not exist

precise Does not exist

trusty Does not exist
(trusty was ignored [abandoned])
upstream
Released (2.6.12~rc2)
xenial Does not exist

linux-oem
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.15.0-1002.3)
cosmic Not vulnerable
(4.15.0-1004.5)
precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Ignored
(was needs-triage now end-of-life)
linux-oracle
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.15.0-1007.9)
cosmic Not vulnerable

precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.15.0-1007.9~16.04.1)
linux-raspi2
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(4.13.0-1005.5)
cosmic
Released (4.18.0-1007.9)
precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.2.0-1013.19)
linux-snapdragon
Launchpad, Ubuntu, Debian
bionic Not vulnerable

cosmic Does not exist

precise Does not exist

trusty Does not exist

upstream
Released (2.6.12~rc2)
xenial Not vulnerable
(4.4.0-1012.12)