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cve[email protected]CVE-2023-43634
HistorySep 21, 2023 - 2:15 p.m.

CVE-2023-43634

2023-09-2114:15:11
CWE-922
CWE-522
web.nvd.nist.gov
17
cve-2023-43634
vault key
secure boot
pcrs
config partition
boot measurement
device security

8.8 High

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

8.4 High

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

9.1%

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”

Affected configurations

NVD
Node
lfedgeeveRange<8.6.0
OR
lfedgeeveRange9.0.09.5.0

CNA Affected

[
  {
    "defaultStatus": "unaffected",
    "packageName": "EVE OS",
    "product": "EVE OS",
    "programFiles": [
      "https://github.com/lf-edge/eve/tree/master/pkg/pillar/evetpm/tpm.go",
      "https://github.com/lf-edge/eve/tree/master/pkg/grub/rootfs.go",
      "https://github.com/lf-edge/eve/tree/master/pkg/measure-config/src/measurefs.go"
    ],
    "repo": "https://github.com/lf-edge/eve",
    "vendor": " LF-Edge, Zededa",
    "versions": [
      {
        "lessThan": "8.6.0",
        "status": "affected",
        "version": "0",
        "versionType": "release"
      },
      {
        "lessThan": "9.5.0",
        "status": "affected",
        "version": "9.0.0",
        "versionType": "release"
      }
    ]
  }
]

8.8 High

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

8.4 High

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

9.1%

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