CVE-2020-15705

GRUB2: avoid loading unsigned kernels when GRUB is booted directly under secureboot without shim

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.

Category

6.4
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.02%
Vendor Advisory ubuntu.com Vendor Advisory ubuntu.com Vendor Advisory debian.org Vendor Advisory redhat.com Vendor Advisory suse.com Vendor Advisory suse.com Vendor Advisory ubuntu.com Vendor Advisory opensuse.org Vendor Advisory opensuse.org Vendor Advisory gentoo.org Vendor Advisory gnu.org Vendor Advisory microsoft.com
Affected: Ubuntu grub2 in Ubuntu
Published at:
Updated at:

References

Link Tags
https://www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/ third party advisory
https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass third party advisory vendor advisory
http://ubuntu.com/security/notices/USN-4432-1 third party advisory vendor advisory
https://www.debian.org/security/2020-GRUB-UEFI-SecureBoot third party advisory vendor advisory
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/ADV200011 patch vendor advisory third party advisory
https://access.redhat.com/security/vulnerabilities/grub2bootloader third party advisory vendor advisory
https://www.suse.com/c/suse-addresses-grub2-secure-boot-issue/ third party advisory vendor advisory
https://www.suse.com/support/kb/doc/?id=000019673 third party advisory vendor advisory
https://www.openwall.com/lists/oss-security/2020/07/29/3 third party advisory mailing list
https://lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.html vendor advisory issue tracking
http://www.openwall.com/lists/oss-security/2020/07/29/3 third party advisory mailing list
https://security.netapp.com/advisory/ntap-20200731-0008/ third party advisory
https://usn.ubuntu.com/4432-1/ third party advisory vendor advisory
http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00067.html vendor advisory mailing list third party advisory
http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00069.html vendor advisory mailing list third party advisory
http://www.openwall.com/lists/oss-security/2021/03/02/3 third party advisory mailing list
https://security.gentoo.org/glsa/202104-05 third party advisory vendor advisory
http://www.openwall.com/lists/oss-security/2021/09/17/2 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/09/17/4 third party advisory mailing list
http://www.openwall.com/lists/oss-security/2021/09/21/1 third party advisory mailing list

Frequently Asked Questions

What is the severity of CVE-2020-15705?
CVE-2020-15705 has been scored as a medium severity vulnerability.
How to fix CVE-2020-15705?
To fix CVE-2020-15705, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2020-15705 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2020-15705 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2020-15705?
CVE-2020-15705 affects Ubuntu grub2 in Ubuntu.
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