Vulnerability · Published Jul 29, 2020 · Assigned by canonical

CVE-2020-15707GRUB2 contained integer overflows when handling the initrd command, leading to a heap-based buffer overflow.

Medium 5.7

In plain English

A medium-severity race condition in grub2 in Ubuntu from Ubuntu. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.6% (higher than 76% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.7Medium

Exploit odds (30 days)1.6%top 24.3% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official description

Integer overflows were discovered in the functions grub_cmd_initrd and grub_initrd_init in the efilinux component of GRUB2, as shipped in Debian, Red Hat, and Ubuntu (the functionality is not included in GRUB2 upstream), leading to a heap-based buffer overflow. These could be triggered by an extremely large number of arguments to the initrd command on 32-bit architectures, or a crafted filesystem with very large files on any architecture. An attacker could use this to execute arbitrary code and bypass UEFI Secure Boot restrictions. This issue affects GRUB2 version 2.04 and prior versions.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Alpine:v3.20	grub	2.06-r0	ALPINE-CVE-2020-15707
Alpine:v3.21	grub	2.06-r0	ALPINE-CVE-2020-15707
Alpine:v3.22	grub	2.06-r0	ALPINE-CVE-2020-15707
Alpine:v3.23	grub	2.06-r0	ALPINE-CVE-2020-15707
Alpine:v3.24	grub	2.06-r0	ALPINE-CVE-2020-15707
Debian:12	grub2	2.04-9	DEBIAN-CVE-2020-15707
Debian:13	grub2	2.04-9	DEBIAN-CVE-2020-15707
Debian:14	grub2	2.04-9	DEBIAN-CVE-2020-15707

Affected products (as reported)

Vendor	Product	Versions
Ubuntu	grub2 in Ubuntu	20.04 LTS – before 2.04-1ubuntu26.118.04 LTS – before 2.02-2ubuntu8.1616.04 LTS – before 2.02~beta2-36ubuntu3.2614.04 ESM – before 2.02~beta2-9ubuntu1.20

Weakness: CWE-362 · Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:H

References

https://www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/ x_refsource_CONFIRM
https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass vendor-advisory, x_refsource_UBUNTU
http://ubuntu.com/security/notices/USN-4432-1 vendor-advisory, x_refsource_UBUNTU
https://www.debian.org/security/2020-GRUB-UEFI-SecureBoot vendor-advisory, x_refsource_DEBIAN
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/ADV200011 x_refsource_CONFIRM
https://access.redhat.com/security/vulnerabilities/grub2bootloader vendor-advisory, x_refsource_REDHAT
https://www.suse.com/c/suse-addresses-grub2-secure-boot-issue/ vendor-advisory, x_refsource_SUSE
https://www.suse.com/support/kb/doc/?id=000019673 vendor-advisory, x_refsource_SUSE
https://www.openwall.com/lists/oss-security/2020/07/29/3 x_refsource_CONFIRM
https://lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.html x_refsource_CONFIRM
DSA-4735 vendor-advisory, x_refsource_DEBIAN
[oss-security] 20200729 multiple secure boot grub2 and linux kernel vulnerabilities mailing-list, x_refsource_MLIST
https://security.netapp.com/advisory/ntap-20200731-0008/ x_refsource_CONFIRM
USN-4432-1 vendor-advisory, x_refsource_UBUNTU
openSUSE-SU-2020:1169 vendor-advisory, x_refsource_SUSE
openSUSE-SU-2020:1168 vendor-advisory, x_refsource_SUSE
GLSA-202104-05 vendor-advisory, x_refsource_GENTOO