Impact

Measured boot validates BIOS, grub, kernel cmdline, and initrd but not the entire rootfs. Thus, an attacker can create an EVE-OS rootfs squashfs image with some files modified and take out the disk and replace the existing rootfs image without that being detected by measure boot and remote attestation.

Patches

Fixed in 8.6.0 and 8.12.1-lts

Workarounds

None

Impact

On boot, the Pillar container checks for /config/authorizedkeys. If present with a valid public key, it enables SSH on port 22 with root login. The /config partition is not protected by measured boot, is mutable and unencrypted.

This enables an attacker with physical access to the device to take out the disk, modify the /config partition using a separate server, then insert it, without the inserted key being flagged as an integrity voilation my measured boot and remote attestation.

Patches

Patched in 9.4.3-lts

Workarounds

None (apart from preventing physical access to the device)

Impact PCR14 is not included in the list of PCRs that seal/unseal the vault key. Additionally, the vault key uses SHA1 PCRs instead of SHA256. Thus an attacker with physical access can take out the disk, use a different computer to modify the files in the /config partition, and re-insert the disk and boot without the change being detected by measured boot and remote attestation.

Patches

Fixed in EVE version 9.4.3-lts

Workarounds

None (apart from preventing physical access to the device)

Resources

https://help.zededa.com/hc/en-us/articles/43295940828827-TPM-PCR-Index-Security-Implications https://github.com/lf-edge/eve/commit/d9383a7ee4e1c39f5c8c6d4a63cb2ebd00695e8a