CVE-2020-14372

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Last Modified: UTC

Moderate Moderate Impact What does this mean?
7.5 CVSS v3 Base Score

Description

A flaw was found in GRUB 2, where it incorrectly enables the usage of the ACPI command when Secure Boot is enabled. This flaw allows an attacker with privileged access to craft a Secondary System Description Table (SSDT) containing code to overwrite the Linux kernel lockdown variable content directly into memory. The kernel further loads and executes the table, defeating its Secure Boot lockdown and allowing the attacker to load unsigned code.

Statement

For a successful attack to occur, the attacker needs to triage the environment to determine where the lockdown variable symbol is placed in memory when the kernel is loaded. Then the SSDT table needs to be written accordingly into this memory position and the grub.cfg file needs to be changed to load the table during the boot time.

Additional Information

External References

Content from www.cve.org is not included.https://www.cve.org/CVERecord?id=CVE-2020-14372

Content from nvd.nist.gov is not included.https://nvd.nist.gov/vuln/detail/CVE-2020-14372

This content is not included.https://access.redhat.com/security/vulnerabilities/RHSB-2021-003

Affected Packages and Issued Red Hat Security Errata

Products / Services Components State Errata
Red Hat Enterprise Linux 7 fwupd Affected
Red Hat Enterprise Linux 7 fwupdate Affected
Red Hat Enterprise Linux 7 grub2 Fixed RHSA-2021:0699
Red Hat Enterprise Linux 7 shim Not affected
Red Hat Enterprise Linux 7.2 Advanced Update Support grub2 Fixed RHSA-2021:0704
Red Hat Enterprise Linux 7.3 Advanced Update Support grub2 Fixed RHSA-2021:0703
Red Hat Enterprise Linux 7.4 Advanced Update Support grub2 Fixed RHSA-2021:0702
Red Hat Enterprise Linux 7.4 Telco Extended Update Support grub2 Fixed RHSA-2021:0702
Red Hat Enterprise Linux 7.4 Update Services for SAP Solutions grub2 Fixed RHSA-2021:0702
Red Hat Enterprise Linux 7.6 Extended Update Support grub2 Fixed RHSA-2021:0701
Unless explicitly stated as not affected, all previous versions of packages in any minor update stream of a product listed here should be assumed vulnerable, although may not have been subject to full analysis.

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authorities (CNA) source for its products and services (see Red Hat classifications ).

CVSS v3 Score Breakdown Red Hat NVD
CVSS v3 Base Score 7.5 7.5
Attack Vector Local Local
Attack Complexity High High
Privileges Required High High
User Interaction None None
Scope Changed Changed
Confidentiality Impact High High
Integrity Impact High High
Availability Impact High High

CVSS v3 Vector

Red Hat CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

NVD CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

Acknowledgements

Red Hat would like to thank Máté Kukri for reporting this issue.

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

 For open source software shipped by multiple vendors, the CVSS base scores may vary for each vendor's version depending on the version they ship, how they ship it, the platform, and even how the software is compiled. This makes scoring of vulnerabilities difficult for third-party vulnerability databases such as NVD that only provide a single CVSS base score for each vulnerability. Red Hat scores reflect how a vulnerability affects our products specifically.

For more information, see https://access.redhat.com/solutions/762393.

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
  • "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
  • "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.

What can I do if my product is listed as "Will not fix"?

 A "will not fix" status means that a fix for an affected product version is not planned or not possible due to complexity, which may create additional risk.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.

What can I do if my product is listed as "Fix deferred"?

 A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
  • Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.

What is a mitigation?

 A mitigation is an action that can be taken to reduce the impact of a security vulnerability, without deploying any fixes.

I have a Red Hat product but it is not in the above list, is it affected?

 The listed products were found to include one or more of the components that this vulnerability affects. These products underwent a thorough evaluation to determine their affectedness by this vulnerability. Note that layered products (such as container-based offerings) that consume affected components from any of the products listed in this table may be affected and are not represented.

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

 In order to maintain code stability and compatibility, Red Hat usually does not rebase packages to entirely new versions. Instead, we backport fixes and new features to an older version of the package we distribute. This can result in some security scanners that only consider the package version to report the package as vulnerable. To avoid this, we suggest that you use an approved vulnerability scanner from our This content is not included.Red Hat Vulnerability Scanner Certification program.