CVE-2023-43636

/// Technical 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 contro

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References