CVE-2023-43634
An attacker could modify the config partition without triggering the measured boot, this could result in the attacker gaining full control over the device with full access to the contents of the encrypted “vault”
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.16%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
When sealing/unsealing the “vault” key, a list of PCRs is used, which defines which PCRs are used. In a previous project, CYMOTIVE found that the configuration is not protected by the secure boot, and in response Zededa implemented measurements on the config partition that was mapped to PCR 13. In that process, PCR 13 was added to the list of PCRs that seal/unseal the key. In commit “56e589749c6ff58ded862d39535d43253b249acf”, the config partition measurement moved from PCR 13 to PCR 14, but PCR 14 was not added to the list of PCRs that seal/unseal the key. This change makes the measurement of PCR 14 effectively redundant as it would not affect the sealing/unsealing of the key. An attacker could modify the config partition without triggering the measured boot, this could result in the attacker gaining full control over the device with full access to the contents of the encrypted “vault”
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- EPSS
- 0.16% probability · 5th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-522, CWE-922
- Affected
- lfedge/eve
- Source
- cve@asrg.io
References
- https://asrg.io/security-advisories/cve-2023-43634/Third Party Advisory
- https://asrg.io/security-advisories/cve-2023-43634/Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.