LF-Edge EVE OS up to 8.5.x/9.4.x Measured Boot data authenticity

Summaryinfo

A vulnerability categorized as critical has been discovered in LF-Edge EVE OS up to 8.5.x/9.4.x. The impacted element is an unknown function of the component Measured Boot. Such manipulation leads to data authenticity. This vulnerability is listed as CVE-2023-43636. The attack must be carried out locally. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in LF-Edge EVE OS up to 8.5.x/9.4.x. It has been rated as critical. Affected by this issue is an unknown functionality of the component Measured Boot. The manipulation with an unknown input leads to a data authenticity vulnerability. Using CWE to declare the problem leads to CWE-345. The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The weakness was presented 09/20/2023. The advisory is available at asrg.io. This vulnerability is handled as CVE-2023-43636. The technical details are unknown and an exploit is not available.

Upgrading to version 8.6.0 or 9.5.0 eliminates this vulnerability.

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Productinfo

Vendor

• LF-Edge

Name

• EVE OS

Version

• 8.0
• 8.1
• 8.2
• 8.3
• 8.4
• 8.5
• 9.0
• 9.1
• 9.2
• 9.3
• 9.4

CPE 2.3info

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CPE 2.2info

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