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Modicon M340 Bmxp341000 FirmwareOperating system · Schneider Electric

CVE-2023-6408

HIGH · 8.1 CVSS v3.1 Published 2024-02-14
Fix available
A fix is available. Upgrade to 3.60 or later.
See remediation →
90/100
Remediation priority · Urgent
Remotely reachable No privileges 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
CWE-924: Improper Enforcement of Message Integrity During Transmission in a Communication Channel vulnerability exists that could cause a denial of service and loss of confidentiality, integrity of controllers when conducting a Man in the Middle attack.

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 · moderate confidence

This is a CWE-924 vulnerability where message integrity is not properly enforced during transmission, allowing an attacker positioned between communicating parties (Man in the Middle) to intercept and potentially modify communications between controllers and their management systems without detection.

MitigationImplement cryptographic message authentication codes (MACs) or digital signatures for all communication channels between controllers and management systems to ensure message integrity during transmission.

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
Modicon M340 Bmxp341000 FirmwareOperating system
Affected:< 3.60
Modicon M340 Bmxp341000h FirmwareOperating system
Affected:< 3.60
Modicon M340 Bmxp342000 FirmwareOperating system
Affected:< 3.60
Modicon M340 Bmxp342010 FirmwareOperating system
Affected:< 3.60
Modicon M340 Bmxp3420102 FirmwareOperating system
Affected:< 3.60
Modicon M340 Bmxp3420102cl FirmwareOperating system
Affected:< 3.60
Modicon M340 Bmxp342020 FirmwareOperating system
Affected:< 3.60
Modicon M340 Bmxp342020h FirmwareOperating system
Affected:< 3.60

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
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/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. Identify the Modicon M340 model number
    Locate the physical PLC unit or check the system inventory for the model number printed on the CPU module. Look for model identifiers: Bmxp341000, Bmxp341000h, Bmxp342000, Bmxp342010, Bmxp3420102, Bmxp3420102cl, Bmxp342020, or Bmxp342020h.
    Affected if The installed model matches any of the listed affected model numbers.
  2. Check the installed firmware version
    Access the PLC through Schneider Electric programming software (such as Unity Pro or EcoStruxure) and navigate to the CPU properties or system information to retrieve the firmware version. Alternatively, check via the web interface or console if available.
    Affected if The firmware version is below 3.60.
  3. Verify the communication channel integrity configuration
    Examine the network communication settings between the PLC and management systems. Check whether any message authentication, digital signatures, or integrity verification mechanisms are configured for the protocol in use (such as Modbus/TCP or other industrial protocols).
    Affected if No message integrity verification (MACs, digital signatures, or equivalent) is configured on the communication channels.

The environment is affected if a Modicon M340 model from the affected list is running firmware version 3.60 or lower and the communication channels lack message integrity protection.

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 3.60 or later
Fixed in 3.60
Interim mitigation

Implement cryptographic message authentication codes (MACs) or digital signatures for all communication channels between controllers and management systems to ensure message integrity during transmission.

Recommended fix Moderate confidence

Firmware version 3.60

  1. Identify all affected Modicon M340 PLCs in the inventory and document their current firmware versions
  2. Download the firmware version 3.60 or later from Schneider Electric's official support portal (download.schneider-electric.com)
  3. Review Schneider Electric's firmware upgrade documentation for Modicon M340 controllers
  4. Establish a maintenance window and implement a backup strategy for the PLC project/program
  5. Connect to the PLC using Unity Pro or EcoStruxure Control Expert programming software
  6. Upload the current project from the PLC for backup purposes
  7. Transfer the new firmware (version 3.60) to the PLC using the programming software's firmware update function
  8. Verify the firmware update was successful by checking the PLC's firmware version
Caveat Review application compatibility before upgrading; legacy projects may require validation after firmware update

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

Fix this in Modicon M340 Bmxp341000 Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation24.0 h
  • Testing16.0 h
  • Review / QA8.0 h
56.0 hours of engineering $9,760
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $15,616.

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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-2023-6408 in production — separate from our analysis above.

No notes yet

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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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data