Upstream information

CVE-2023-43636 at MITRE

Description




In EVE OS, the “measured boot” mechanism prevents a compromised device from accessing
the encrypted data located in the vault.

As per the “measured boot” design, the PCR values calculated at different stages of the boot
process will change if any of their respective parts are changed.

This includes, among other things, the configuration of the bios, grub, the kernel cmdline,
initrd, and more.

However, this mechanism does not validate the entire rootfs, so an attacker can edit the
filesystem and gain control over the system.

As the default filesystem used by EVE OS is squashfs, this is somewhat harder than an ext4,
which is easily changeable.

This will not stop an attacker, as an attacker can repackage the squashfs with their changes
in it and replace the partition altogether.

This can also be done directly on the device, as the “003-storage-init” container contains the
“mksquashfs” and “unsquashfs” binaries (with the corresponding libs).







An attacker can gain full control over the device without changing the PCR values, thus not
triggering the “measured boot” mechanism, and having full access to the vault.



Note:

This issue was partially fixed in these commits (after disclosure to Zededa), where the config
partition measurement was added to PCR13:

• aa3501d6c57206ced222c33aea15a9169d629141

• 5fef4d92e75838cc78010edaed5247dfbdae1889.

This issue was made viable in version 9.0.0 when the calculation was moved to PCR14 but it was not included in the measured boot.

SUSE information

Overall state of this security issue: Resolved

This issue is currently rated as having important severity.

CVSS v3 Scores
CVSS detail National Vulnerability Database
Base Score 8.8
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Changed
Confidentiality Impact High
Integrity Impact High
Availability Impact High
CVSSv3 Version 3.1
No SUSE Bugzilla entries cross referenced.

SUSE Security Advisories:

List of released packages

Product(s) Fixed package version(s) References

Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.

Product(s) Source package State
Products under general support and receiving all security fixes.
openSUSE Leap 15.6 govulncheck-vulndb Released
Products past their end of life and not receiving proactive updates anymore.
SUSE Linux Enterprise Module for Package Hub 15 SP5 govulncheck-vulndb Affected
SUSE Linux Enterprise Module for Package Hub 15 SP6 govulncheck-vulndb Affected
openSUSE Leap 15.5 govulncheck-vulndb Affected

SUSE Timeline for this CVE

CVE page created: Wed Sep 20 18:00:51 2023
CVE page last modified: Wed Mar 4 19:13:36 2026