CVE intelligence and bounded remediation

CVE-2020-6988 — Rockwellautomation Micrologix 1400 A Firmware security vulnerability

High CVSS 7.5

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, A remote, unauthenticated attacker can send a request from the RSLogix 500 software to the victim’s MicroLogix controller. The controller will then respond to the client with used password values to authenticate the user on the client-side. This method of authentication may allow an attacker to bypass authentication altogether, disclose sensitive information, or leak credentials.

Severity
High
CVSS
7.5 (3.1)
Published
2020-03-16
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-603, CWE-287

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

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

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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