CVE intelligence and bounded remediation

CVE-2020-6990 — Rockwellautomation Micrologix 1400 A Firmware security vulnerability

Critical CVSS 9.8

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.

Severity
Critical
CVSS
9.8 (3.1)
Published
2020-03-16
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-321, CWE-798

Affected products

  • rockwellautomation / micrologix_1400_a_firmware
  • rockwellautomation / micrologix_1400_b_firmware
  • rockwellautomation / micrologix_1100_firmware
  • rockwellautomation / rslogix_500

Matched remediation archetype

Authentication bypass and missing authentication

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Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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