Micrologix 1400 A FirmwareOperating system · Rockwellautomation

CVE-2020-6990

CRITICAL · 9.8 CVSS v3.1 Published 2020-03-16
Fix available
A fix is available. Upgrade to after 21.001 or later.
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
Rockwell Automation MicroLogix 1400 Controllers Series B v21.001 and prior, Series A, all versions, MicroLogix 1100 Controller, all versions, RSLogix 500 Software v12.001 and prior, The cryptographic key utilized to help protect the account password is hard coded into the RSLogix 500 binary file. An attacker could identify cryptographic keys and use it for further cryptographic attacks that could ultimately lead to a remote attacker gaining unauthorized access to the controller.

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 RSLogix 500 software contains a hardcoded cryptographic key embedded in its binary that is used to protect account passwords for MicroLogix 1100 and 1400 controllers. An attacker can extract this key from the software binary and use it to decrypt or bypass authentication, potentially gaining unauthorized remote access to the affected controllers.

MitigationUpdate RSLogix 500 to a version beyond v12.001 and update controller firmware to patched versions. Change any passwords that may have been protected by the compromised cryptographic key.

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
Micrologix 1400 A FirmwareOperating system
Affected:all versions
Micrologix 1400 B FirmwareOperating system
Affected:<= 21.001
Micrologix 1100 FirmwareOperating system
Affected:all versions
Rslogix 500Application
Affected:<= 12.001

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. Check installed RSLogix 500 version
    Open RSLogix 500 and navigate to Help > About, or check the executable properties of RSLogix500.exe in the installation directory
    Affected if The version is 12.001 or lower
  2. Identify MicroLogix 1400 B controllers on the network
    Use network scanning tools or check your industrial network inventory for MicroLogix 1400 B controllers. Access the controller via RSLogix 500 or web interface to view firmware version
    Affected if Controller firmware version is 21.001 or lower
  3. Identify MicroLogix 1100 and 1400 A controllers on the network
    Scan the network for MicroLogix 1100 and 1400 A controllers using network discovery tools or controller enumeration, then query each controller for its firmware version
    Affected if Any MicroLogix 1100 or MicroLogix 1400 A controllers are present on the network (all versions are affected)
  4. Check if controller password protection is enabled
    Connect to each affected MicroLogix controller using RSLogix 500 and verify if security/password features are configured under the controller security settings
    Affected if Password protection or authentication is enabled on the controller, as the hardcoded key protects these credentials

You are affected if RSLogix 500 version 12.001 or lower is installed, OR any MicroLogix 1100, MicroLogix 1400 A, or MicroLogix 1400 B (firmware <=21.001) controllers with password protection are present on your network.

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
Upgrade available Upgrade to a release after 21.001
Interim mitigation

Update RSLogix 500 to a version beyond v12.001 and update controller firmware to patched versions. Change any passwords that may have been protected by the compromised cryptographic key.

Fix this in Micrologix 1400 A Firmware Scoped from the published advisory
  • Consultation12.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
40.0 hours of engineering $7,200
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $11,520.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2020-6990 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2020-6990 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