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EveOperating system · Lfedge

CVE-2023-43633

HIGH · 8.8 CVSS v3.1 Published 2023-09-21
Fix available
A fix is available. Upgrade to 8.6.0 / 9.5.0 or later.
See remediation →
90/100
Remediation priority · Urgent
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
On boot, the Pillar eve container checks for the existence and content of “/config/GlobalConfig/global.json”. If the file exists, it overrides the existing configuration on the device on boot. This allows an attacker to change the system’s configuration, which also includes some debug functions. This could be used to unlock the ssh with custom “authorized_keys” via the “debug.enable.ssh” key, similar to the “authorized_keys” finding that was noted before. Other usages include unlocking the usb to enable the keyboard via the “debug.enable.usb” key, allowing VNC access via the “app.allow.vnc” key, and more. An attacker could easily enable these debug functionalities without triggering the “measured boot” mechanism implemented by EVE OS, and without marking the device as “UUD” (“Unknown Update Detected”). This is because the “/config” partition is not protected by “measured boot”, it is mutable and it is not encrypted in any way. An attacker can gain full control over the device without changing the PCR values, thereby 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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Pillar eve container in Zededa EVE-OS checks for and applies /config/GlobalConfig/global.json on boot, overriding device configuration. An attacker with filesystem access can enable debug features (ssh, usb, vnc) by modifying this file, bypassing measured boot protection since the /config partition is mutable, unencrypted, and was not included in PCR measurements (introduced in v9.0.0).

MitigationEnsure the /config partition is included in measured boot PCR calculations (PCR13 per the fix commits), and upgrade to versions after the partial fixes. Verify PCR values change when /config is modified.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
EveOperating system
Affected:< 8.6.0>= 9.0.0, < 9.5.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed EVE-OS version
    Run 'viptool version' or check /hostfs/etc/eve-version file to determine the running EVE-OS version
    Affected if Version is less than 8.6.0, or greater than or equal to 9.0.0 but less than 9.5.0
  2. Verify /config partition exists and is mounted
    Check if /config partition is present by running 'ls /config' or 'mount | grep /config' on the EVE device
    Affected if The /config partition exists and is mounted as a mutable, writable partition
  3. Inspect global.json for debug feature configuration
    Read the file /config/GlobalConfig/global.json and check if any of 'ssh', 'usb', or 'vnc' debug features are set to enabled or true
    Affected if The global.json file exists and contains debug feature settings (ssh, usb, or vnc) set to enabled/true values
  4. Check if PCR13 includes /config partition measurements
    Query the TPM PCR values using 'tpm2_pcrread' or check boot measurement logs to verify PCR13 includes /config partition hash
    Affected if PCR13 does not include /config partition measurements, or the /config partition was not included in the measured boot chain

A user is affected if running a vulnerable EVE-OS version (less than 8.6.0, or 9.0.0 to less than 9.5.0) with a writable /config partition that is not measured in PCR13, and the global.json file contains enabled debug features.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 8.6.0 / 9.5.0 or later
Fixed in 8.6.09.5.0
Interim mitigation

Ensure the /config partition is included in measured boot PCR calculations (PCR13 per the fix commits), and upgrade to versions after the partial fixes. Verify PCR values change when /config is modified.

Recommended fix High confidence

Eve OS 9.5.0 or later

  1. 1. Identify the current Eve OS version running on affected devices using 'osinfo' or the EVE CLI tools.
  2. 2. Plan for a maintenance window as the upgrade will require a device reboot.
  3. 3. Obtain the upgrade image for Eve OS version 9.5.0 or later from the official Zededa/Eve OS release channels.
  4. 4. Verify the integrity of the upgrade image using published checksums.
  5. 5. Initiate the upgrade process using the EVE CLI: 'evectl upgrade --version <target-version>' or through the EVE controller/management interface.
  6. 6. After the upgrade completes, verify the device is running version 9.5.0 or later.
  7. 7. Confirm that the /config/GlobalConfig/global.json file is now properly measured by PCR14 as part of the verified boot chain.
Caveat Review release notes for 9.5.0 to check for any configuration or API changes that may affect existing deployments

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Eve Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-43633 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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