CVE-2020-15705 — Improper Verification of Cryptographic Signature in Grub2 IN Ubuntu
Severity
6.4MEDIUMNVD
EPSS
0.0%
top 93.70%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
Timeline
PublishedJul 29
Latest updateMay 24
Description
GRUB2 fails to validate kernel signature when booted directly without shim, allowing secure boot to be bypassed. This only affects systems where the kernel signing certificate has been imported directly into the secure boot database and the GRUB image is booted directly without the use of shim. This issue affects GRUB2 version 2.04 and prior versions.
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:HExploitability: 0.5 | Impact: 5.9
Affected Packages7 packages
Also affects: Debian Linux 10.0, Ubuntu Linux 14.04, 16.04, 18.04, 20.04, Enterprise Linux 7.0, 8.0, Openshift Container Platform 4.0
Patches
🔴Vulnerability Details
3GHSA▶
GHSA-w739-fjv8-98pq: GRUB2 fails to validate kernel signature when booted directly without shim, allowing secure boot to be bypassed↗2022-05-24
OSV▶
CVE-2020-15705: GRUB2 fails to validate kernel signature when booted directly without shim, allowing secure boot to be bypassed↗2020-07-29
CVEList▶
GRUB2: avoid loading unsigned kernels when GRUB is booted directly under secureboot without shim↗2020-07-29
📋Vendor Advisories
6Microsoft▶
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 ↗2021-03-09
Microsoft▶
GRUB2: avoid loading unsigned kernels when GRUB is booted directly under secureboot without shim↗2020-07-14