CVE-2023-43630: PCR14 is not in the list of PCRs that seal/unseal the “vault” key, but due to the change that was implemented in commit…

PriorityP343high8.8CVSS 3.1

AVLACLPRLUINSCCHIHAH

EPSS

0.11%

1.4th percentile

PCR14 is not in the list of PCRs that seal/unseal the “vault” key, but due to the change that was implemented in commit “7638364bc0acf8b5c481b5ce5fea11ad44ad7fd4”, fixing this issue alone would not solve the problem of the config partition not being measured correctly. Also, the “vault” key is sealed/unsealed with SHA1 PCRs instead of SHA256. This issue was somewhat mitigated due to all of the PCR extend functions updating both the values of SHA256 and SHA1 for a given PCR ID. However, due to the change that was implemented in commit “7638364bc0acf8b5c481b5ce5fea11ad44ad7fd4”, this is no longer the case for PCR14, as the code in “measurefs.go” explicitly updates only the SHA256 instance of PCR14, which means that even if PCR14 were to be added to the list of PCRs sealing/unsealing the “vault” key, changes to the config partition would still not be measured. 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”

Affected

3 ranges

Vendor	Product	Version range	Fixed in
github.com	lf-edge_eve	>= 0 < 0.0.0-20230126065759-d9383a7ee4e1	0.0.0-20230126065759-d9383a7ee4e1
lf-edge_zededa	eve_os	>= 9.0.0 < 9.5.0	9.5.0
linuxfoundation	edge_virtualization_engine	>= 9.0.0 < 9.5.0	9.5.0

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