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Micom P141 FirmwareOperating system · Schneider Electric

CVE-2018-7758

MEDIUM · 6.5 CVSS v3.0 Published 2018-04-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
Remediation priority · Elevated
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
A denial of service vulnerability exists in Schneider Electric's MiCOM Px4x (P540 range excluded) with legacy Ethernet board, MiCOM P540D Range with Legacy Ethernet Board, and MiCOM Px4x Rejuvenated could lose network communication in case of TCP/IP open requests on port 20000 (DNP3oE) if an older TCI/IP session is still open with identical IP address and port number.

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

A denial of service vulnerability exists in Schneider Electric MiCOM Px4x (P540 range excluded) and P540D Range devices with legacy Ethernet board, and MiCOM Px4x Rejuvenated. When a TCP/IP open request is made on port 20000 (DNP3oE) while an older TCP/IP session remains open with an identical IP address and port number, the device loses network communication.

MitigationApply vendor-supplied firmware updates to affected MiCOM Px4x and P540D devices. As an interim measure, implement network controls to prevent duplicate TCP connection attempts to port 20000 from identical source IP/port combinations.

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
Micom P141 FirmwareOperating system
Affected:all versions
Micom P142 FirmwareOperating system
Affected:all versions
Micom P143 FirmwareOperating system
Affected:all versions
Micom P145 FirmwareOperating system
Affected:all versions
Micom P642 FirmwareOperating system
Affected:all versions
Micom P643 FirmwareOperating system
Affected:all versions
Micom P645 FirmwareOperating system
Affected:all versions
Micom P849 FirmwareOperating system
Affected:all versions

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 device model and firmware version
    Locate the MiCOM device nameplate or access the device web interface/HMI to confirm the model number (P141, P142, P143, P145, P642, P643, P645, or P849) and note the firmware version. Exclude P540 range devices as they are not affected.
    Affected if The device is any of P141, P142, P143, P145, P642, P643, P643, P645, or P849 (all firmware versions are affected)
  2. Verify if DNP3 over Ethernet (port 20000) is enabled
    Access the device configuration through its management interface or engineering software and check whether the DNP3oE protocol is enabled on TCP port 20000.
    Affected if DNP3 over Ethernet on port 20000 is configured and active on the device
  3. Check for legacy Ethernet board configuration
    Through the device management interface or technical documentation, determine whether the device uses a legacy Ethernet board (as opposed to newer Ethernet hardware).
    Affected if The device has a legacy Ethernet board installed
  4. Monitor for duplicate TCP session conditions
    On the network segment, monitor TCP connections to port 20000. Look for scenarios where a new TCP connection is initiated from the same source IP address and source port combination while a previous session remains open.
    Affected if Duplicate TCP connection attempts to port 20000 from identical source IP/port combinations are occurring on the network

The environment is affected if the device is a MiCOM P141, P142, P143, P145, P642, P643, P645, or P849 with DNP3 over Ethernet enabled on port 20000, and there is potential for duplicate TCP connections from the same source IP/port combination.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-supplied firmware updates to affected MiCOM Px4x and P540D devices. As an interim measure, implement network controls to prevent duplicate TCP connection attempts to port 20000 from identical source IP/port combinations.

Fix this in Micom P141 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2018-7758 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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