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Cs1w Eip21 FirmwareOperating system · Omron

CVE-2023-27396

CRITICAL · 9.8 CVSS v3.1 Published 2023-06-19
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
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
FINS (Factory Interface Network Service) is a message communication protocol, which is designed to be used in closed FA (Factory Automation) networks, and is used in FA networks composed of OMRON products. Multiple OMRON products that implement FINS protocol contain following security issues -- (1)Plaintext communication, and (2)No authentication required. When FINS messages are intercepted, the contents may be retrieved. When arbitrary FINS messages are injected, any commands may be executed on, or the system information may be retrieved from, the affected device. Affected products and versions are as follows: SYSMAC CS-series CPU Units, all versions, SYSMAC CJ-series CPU Units, all versions, SYSMAC CP-series CPU Units, all versions, SYSMAC NJ-series CPU Units, all versions, SYSMAC NX1P-series CPU Units, all versions, SYSMAC NX102-series CPU Units, all versions, and SYSMAC NX7 Database Connection CPU Units (Ver.1.16 or later)

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 FINS protocol used by OMRON SYSMAC PLCs (CS, CJ, CP, NJ, NX1P, NX102, NX7 series) transmits all communications in plaintext and requires no authentication, allowing any network actor to intercept readable messages or inject arbitrary commands to execute functions or exfiltrate system data from affected CPU units.

MitigationIsolate FINS-enabled devices behind network segmentation firewalls, block external FINS traffic at perimeter controls, and monitor for unauthorized FINS command activity; for NX7 units ensure version 1.16 or later is deployed.

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
Cs1w Eip21 FirmwareOperating system
Affected:all versions
Cs1w Spu01 V2 FirmwareOperating system
Affected:all versions
Cs1w Spu02 V2 FirmwareOperating system
Affected:all versions
Cs1w Etn21 FirmwareOperating system
Affected:all versions
Cs1w Clk FirmwareOperating system
Affected:all versions
Cs1w Fln22 FirmwareOperating system
Affected:all versions
Cs1w Drm21 V1 FirmwareOperating system
Affected:all versions
Cs1w Nc271 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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/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 OMRON PLC models in the environment
    Review network scans, asset inventories, or physically inspect PLC hardware labels to determine if any CPU units from the CS, CJ, CP, NJ, NX1P, NX102, or NX7 series are present
    Affected if Any of these PLC series are found in the environment
  2. Verify FINS protocol is enabled on PLCs
    Access the PLC programming software (CX-Programmer or Sysmac Studio) and check the PLC setup or network configuration for FINS protocol settings; look for FINS/UDP or FINS/TCP enabled status
    Affected if FINS protocol is enabled on the CPU unit
  3. Check network exposure of FINS service ports
    Scan the network for open ports 9600/UDP and 9600/TCP (standard FINS ports) or perform a packet capture to detect FINS traffic on the network
    Affected if FINS ports are accessible from network segments outside the local PLC communication zone
  4. Verify NX7 firmware version
    For NX7 series PLCs specifically, check the firmware version through Sysmac Studio or the PLC hardware diagnostic screen
    Affected if The NX7 unit is running firmware version earlier than 1.16

If OMRON PLCs from the affected CS, CJ, CP, NJ, NX1P, NX102, or NX7 series are present AND FINS protocol is enabled, the environment is vulnerable to plaintext FINS traffic interception and injection attacks.

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

Isolate FINS-enabled devices behind network segmentation firewalls, block external FINS traffic at perimeter controls, and monitor for unauthorized FINS command activity; for NX7 units ensure version 1.16 or later is deployed.

Fix this in Cs1w Eip21 Firmware Scoped from the published advisory
  • Consultation12.0 h
  • Implementation20.0 h
  • Testing12.0 h
  • Review / QA8.0 h
52.0 hours of engineering $9,240
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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-2023-27396 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