CVE-2020-15705 - Improper Verification of Cryptographic Signature

Severity

64%

Complexity

5%

Confidentiality

98%

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 3.1 Base Score 6.4. CVSS Attack Vector: local. CVSS Attack Complexity: high. CVSS Vector: (CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H).

CVSS 2.0 Base Score 4.4. CVSS Attack Vector: local. CVSS Attack Complexity: medium. CVSS Vector: (AV:L/AC:M/Au:N/C:P/I:P/A:P).

Demo Examples

Improper Verification of Cryptographic Signature

CWE-347

In the following code, a JarFile object is created from a downloaded file.


               
JarFile jf = new JarFile(f);

The JAR file that was potentially downloaded from an untrusted source is created without verifying the signature (if present). An alternate constructor that accepts a boolean verify parameter should be used instead.

Overview

First reported 4 years ago

2020-07-29 18:15:00

Last updated 4 years ago

2020-08-29 18:15:00

Affected Software

GNU GRUB2

Red Hat Enterprise Linux Atomic Host

Red Hat Openshift Container Platform 4.0

4.0

Canonical Ubuntu Linux 14.04 ESM Edition

14.04

Canonical Ubuntu Linux 16.04 LTS (Long-Term Support)

16.04

Canonical Ubuntu Linux 18.04 LTS Edition

18.04

Canonical Ubuntu Linux 20.04 LTS Edition

20.04

Debian Linux 10

10

Red Hat Enterprise Linux (RHEL) 7.0 (7)

7.0

Red Hat Enterprise Linux 8.0

8.0

SUSE Linux Enterprise Server (SLES) 11

11

SUSE Linux Enterprise Server (SLES) 12

12

SUSE Linux Enterprise Server (SLES) 15

15

Microsoft Windows 10 1709

1709

Microsoft Windows 10 1803

1803

Microsoft Windows 10 1809

1809

Microsoft Windows 10 1909

1909

Microsoft Windows RT 8.1

Microsoft Windows Server 2012

Microsoft Windows Server 2016

Microsoft Windows Server 2016 1909

1909

Microsoft Windows Server 2019

References

http://ubuntu.com/security/notices/USN-4432-1

[oss-security] 20200729 multiple secure boot grub2 and linux kernel vulnerabilities

https://access.redhat.com/security/vulnerabilities/grub2bootloader

https://lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.html

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/ADV200011

https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass

https://www.debian.org/security/2020-GRUB-UEFI-SecureBoot

https://www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/

https://www.openwall.com/lists/oss-security/2020/07/29/3

https://www.suse.com/c/suse-addresses-grub2-secure-boot-issue/

https://www.suse.com/support/kb/doc/?id=000019673

https://security.netapp.com/advisory/ntap-20200731-0008/

http://ubuntu.com/security/notices/USN-4432-1

Third Party Advisory

[oss-security] 20200729 multiple secure boot grub2 and linux kernel vulnerabilities

Mailing List, Third Party Advisory

https://access.redhat.com/security/vulnerabilities/grub2bootloader

Third Party Advisory

https://lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.html

Issue Tracking, Vendor Advisory

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/ADV200011

Third Party Advisory

https://security.netapp.com/advisory/ntap-20200731-0008/

Third Party Advisory

https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass

Third Party Advisory

https://www.debian.org/security/2020-GRUB-UEFI-SecureBoot

Third Party Advisory

https://www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/

Third Party Advisory

https://www.openwall.com/lists/oss-security/2020/07/29/3

Mailing List, Third Party Advisory

https://www.suse.com/c/suse-addresses-grub2-secure-boot-issue/

Third Party Advisory

https://www.suse.com/support/kb/doc/?id=000019673

Third Party Advisory

USN-4432-1

openSUSE-SU-2020:1280

openSUSE-SU-2020:1282

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