Improper Authorization in grub - CVE-2020-27779

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Main Vulnerability Database Vulnerabilities #VU51194

Improper Authorization in grub - CVE-2020-27779

Published: March 3, 2021 / Updated: December 17, 2024


Vulnerability identifier: #VU51194
CSH Severity: Low
CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2020-27779
CWE-ID: CWE-285
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to bypass authorization checks.

The vulnerability exists within the cutmem command, which does not honor the Secure Boot locking. A local privileged user can remove address ranges from memory creating an opportunity to circumvent Secure Boot protections after proper triage about grub's memory layout.


Affected software

grub
Debian Linux
Gentoo Linux
Arch Linux
SUSE CaaS Platform
SUSE Manager Proxy
SUSE Manager Retail Branch Server
SUSE Manager Server
SUSE Enterprise Storage
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux for Scientific Computing
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux for Power 9
SUSE OpenStack Cloud
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux EUS Compute Node
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for Power, big endian - Extended Update Support
Red Hat Enterprise Linux for x86_64
Anolis OS
Red Hat Enterprise Linux for ARM 64
SUSE OpenStack Cloud Crowbar
HPE Helion Openstack
Red Hat Enterprise Linux for IBM z Systems
Red Hat CodeReady Linux Builder for ARM 64
Red Hat CodeReady Linux Builder for x86_64
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support
Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support
SUSE Linux Enterprise Debuginfo
SUSE Linux Enterprise Server
SUSE Linux Enterprise Server for SAP
SUSE Linux Enterprise High Performance Computing
SUSE Linux Enterprise Module for Server Applications
SUSE Linux Enterprise Module for Basesystem
Ubuntu
openEuler
Fedora
APM Edge
PowerFlex Appliance
PowerFlex rack
Data Computing Appliance (DCA)
EMC Cloud Tiering Appliance
fwupd (Red Hat package)
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
Red Hat Enterprise Linux Server for x86_64 - Update Services for SAP Solutions
fwupd
grub-efi-arm64-signed (Ubuntu package)
grub-efi-amd64-signed (Ubuntu package)
grub2 (Debian package)
grub2-debugsource
grub2-debuginfo
grub2-x86_64-xen
grub2-x86_64-efi
grub2 (Red Hat package)
grub2-i386-pc
grub2-snapper-plugin
grub2-systemd-sleep-plugin
grub2
grub2-powerpc-ieee1275
grub2-arm64-efi
grub2-s390x-emu
grub-efi-amd64-bin (Ubuntu package)
grub-efi-arm64-bin (Ubuntu package)
grub2-efi-aa64
grub2-efi-aa64-cdboot
grub2-tools
grub2-tools-extra
grub2-efi-aa64-modules
grub2-efi-ia32-cdboot
grub2-tools-minimal
grub2-pc-modules
grub2-efi-x64-modules
grub2-help
grub2-common
grub2-efi-ia32-modules
grub2-pc
grub2-efi-ia32
grub2-tools-efi
grub2-efi-x64
grub2-efi-x64-cdboot
efi-rpm-macros
shim
shim-unsigned-aarch64
shim (Red Hat package)
shim-unsigned-x64
shim-aa64
shim-ia32
shim-x64
shim-unsigned-x64 (Red Hat package)
shim-unsigned-aarch64 (Red Hat package)
IBM Qradar SIEM
Red Hat Advanced Cluster Management for Kubernetes
Dell EMC Storage Monitoring and Reporting (SMR)

How to mitigate CVE-2020-27779

Install updates from vendor's repository.

APM Edge - update to 4.0
fwupd (Red Hat package) - addressed in versions 1.1.4-4.el8_1, 1.1.4-9.el8_2, 1.5.9-1.el8_4
IBM Qradar SIEM - addressed in versions 7.3.3 Fix Pack 9, 7.4.3 Fix Pack 1
PowerFlex Appliance - addressed in versions Intelligent_Catalog_36_360_02_r1, Intelligent_Catalog_36_354_02_r4
fwupd - addressed in versions 1.1.4-9, 1.5.9-1
grub-efi-arm64-signed (Ubuntu package) - addressed in versions 1.167.2+2.04-1ubuntu44.2, 1.167~18.04.5+2.04-1ubuntu44.1.2
grub-efi-amd64-signed (Ubuntu package) - addressed in versions 1.167.2+2.04-1ubuntu44.2, 1.167~18.04.5+2.04-1ubuntu44.1.2
Red Hat Advanced Cluster Management for Kubernetes - update to 2.1.5
grub2 (Debian package) - update to 2.02+dfsg1-20+deb10u4
grub2-debugsource - addressed in versions 2.02-0.66.26.1, 2.02-4.69.1, 2.02-12.47.1, 2.02-19.66.1, 2.02-26.43.1, 2.02-115.59.1, 2.04-9.34.1
grub2-debuginfo - addressed in versions 2.02-0.66.26.1, 2.02-4.69.1, 2.02-12.47.1, 2.02-19.66.1, 2.02-26.43.1, 2.02-115.59.1, 2.04-9.34.1
grub2-x86_64-xen - addressed in versions 2.02-0.66.26.1, 2.02-4.69.1, 2.02-12.47.1, 2.02-19.66.1, 2.02-26.43.1, 2.02-115.59.1, 2.04-9.34.1
grub2-x86_64-efi - addressed in versions 2.02-0.66.26.1, 2.02-4.69.1, 2.02-12.47.1, 2.02-19.66.1, 2.02-26.43.1, 2.02-115.59.1, 2.04-9.34.1
grub2 (Red Hat package) - addressed in versions 2.02-0.86.el7_2.2, 2.02-0.86.el7_3.2, 2.02-0.86.el7_4.2, 2.02-0.86.el7_6.3, 2.02-0.86.el7_7.3, 2.02-0.87.el7_9.2, 2.02-87.el8_1.2, 2.02-90.el8_3.1
grub2-i386-pc - addressed in versions 2.02-4.69.1, 2.02-12.47.1, 2.02-19.66.1, 2.02-26.43.1, 2.02-115.59.1, 2.04-9.34.1
grub2-snapper-plugin - addressed in versions 2.02-4.69.1, 2.02-12.47.1, 2.02-19.66.1, 2.02-26.43.1, 2.02-115.59.1, 2.04-9.34.1
grub2-systemd-sleep-plugin - addressed in versions 2.02-4.69.1, 2.02-12.47.1, 2.02-19.66.1, 2.02-26.43.1, 2.02-115.59.1, 2.04-9.34.1
grub2 - addressed in versions 2.02-4.69.1, 2.02-12.47.1, 2.02-19.66.1, 2.02-26.43.1, 2.02-115.59.1, 2.04-9.34.1
grub2-powerpc-ieee1275 - addressed in versions 2.02-4.69.1, 2.02-12.47.1, 2.02-19.66.1, 2.02-26.43.1, 2.02-115.59.1, 2.04-9.34.1
grub2-arm64-efi - addressed in versions 2.02-4.69.1, 2.02-12.47.1, 2.02-19.66.1, 2.02-26.43.1, 2.04-9.34.1
grub2-s390x-emu - addressed in versions 2.02-4.69.1, 2.02-12.47.1, 2.02-19.66.1, 2.02-26.43.1, 2.02-115.59.1, 2.04-9.34.1
grub-efi-amd64-bin (Ubuntu package) - addressed in versions 2.04-1ubuntu44.1.2, 2.04-1ubuntu44.2
grub-efi-arm64-bin (Ubuntu package) - addressed in versions 2.04-1ubuntu44.1.2, 2.04-1ubuntu44.2
grub2-efi-aa64 - update to 2.04-13
grub2-efi-aa64-cdboot - update to 2.04-13
grub2-tools - update to 2.04-13
grub2-debugsource - update to 2.04-13
grub2-tools-extra - update to 2.04-13
grub2-efi-aa64-modules - update to 2.04-13
grub2-efi-ia32-cdboot - update to 2.04-13
grub2-tools-minimal - update to 2.04-13
grub2-pc-modules - update to 2.04-13
grub2-efi-x64-modules - update to 2.04-13
grub2-help - update to 2.04-13
grub2-common - update to 2.04-13
grub2-efi-ia32-modules - update to 2.04-13
grub2-pc - update to 2.04-13
grub2-efi-ia32 - update to 2.04-13
grub2-tools-efi - update to 2.04-13
grub2-efi-x64 - update to 2.04-13
grub2 - update to 2.04-13
grub2-efi-x64-cdboot - update to 2.04-13
grub2-debuginfo - update to 2.04-13
PowerFlex rack - addressed in versions 3.3.9.2, 3.4.4.2, 3.5.4.2
Data Computing Appliance (DCA) - update to 4.3.0.0
Dell EMC Storage Monitoring and Reporting (SMR) - update to 4.6.0.0
efi-rpm-macros - update to 5-2.fc34
EMC Cloud Tiering Appliance - update to 13.0.0.3.25
shim - addressed in versions 15.4-1, 15.4-4
shim-unsigned-aarch64 - update to 15.4-1.fc34
shim (Red Hat package) - update to 15.4-2.el8_1
shim-unsigned-x64 - update to 15.4-2.fc32
shim-aa64 - update to 15.4-2.0.1
shim-ia32 - update to 15.4-2.0.1
shim-x64 - update to 15.4-2.0.1
shim-unsigned-x64 (Red Hat package) - update to 15.4-4.el8_1
shim-unsigned-aarch64 (Red Hat package) - update to 15-7.el8_1

External References

Related Security Bulletins