Micrologix 1400 FirmwareOperating system · Rockwellautomation

CVE-2018-17924

HIGH · 8.6 CVSS v3.1 Published 2018-12-07
Fix available
A fix is available. Upgrade to after 10.10 or later.
See remediation →
95/100
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 and 1756 ControlLogix Communications Modules An unauthenticated, remote threat actor could send a CIP connection request to an affected device, and upon successful connection, send a new IP configuration to the affected device even if the controller in the system is set to Hard RUN mode. When the affected device accepts this new IP configuration, a loss of communication occurs between the device and the rest of the system as the system traffic is still attempting to communicate with the device via the overwritten IP address.

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

This vulnerability allows an unauthenticated remote attacker to send a CIP connection request to affected MicroLogix 1400 controllers or 1756 ControlLogix communication modules, and upon successful connection, inject a new IP configuration to the device even when the controller is set to Hard RUN mode. When the device accepts this malicious IP configuration, all system communication is disrupted because traffic continues attempting to reach the original IP address.

MitigationImplement network segmentation and firewall rules to restrict CIP traffic to authorized sources only, and apply vendor firmware updates when available. Consider disabling CIP-based IP configuration or implementing network monitoring for unexpected IP changes.

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 FirmwareOperating system
Affected:all versions
1756 Enbt FirmwareOperating system
Affected:all versions
1756 Eweb Series A FirmwareOperating system
Affected:all versions
1756 Eweb Series B FirmwareOperating system
Affected:all versions
1756 En2f Series A FirmwareOperating system
Affected:all versions
1756 En2f Series B FirmwareOperating system
Affected:all versions
1756 En2f Series C FirmwareOperating system
Affected:<= 10.10
1756 En2t Series A 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
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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 the device model and firmware version
    Access the controller's web interface, RSLinx Classic, or use the controller's LCD display to determine the exact model number (e.g., MicroLogix 1400, 1756-ENBT, 1756-EWEB, 1756-EN2F, 1756-EN2T) and firmware revision. For 1756 modules, check via ControlFLASH or the Logix chassis web page.
    Affected if The device is a MicroLogix 1400 (any firmware), or a 1756-ENBT, 1756-EWEB (Series A or B), 1756-EN2F (Series A, B, or Series C <= 10.10), or 1756-EN2T (Series A) communication module.
  2. Verify CIP communication is enabled
    Check the communication module or controller settings via RSLinx Classic (communication setup > network browse) or the device web interface to confirm CIP (Common Industrial Protocol) services are active and the module is listening on CIP ports (typically 44818 for Ethernet/IP).
    Affected if CIP is enabled and the device accepts CIP connections from the network, which is the default vulnerable state for these modules.
  3. Confirm IP configuration method settings
    Examine the controller or communication module IP configuration settings in RSLinx, the web interface, or BootP/DHCP server logs to determine if the device is configured to accept IP settings via CIP/ENET commands. For MicroLogix 1400, check the channel 1 configuration; for 1756 modules, check the network configuration settings.
    Affected if The device allows IP configuration changes via CIP/Network commands (this is the vulnerable setting that enables the attack).
  4. Review network logs for unexpected CIP IP change requests
    Monitor network traffic or firewall logs for CIP Set Attribute Single messages targeting object 0xF5 (TCP/IP interface object) or inspect device syslogs if available. Look for CIP connections from unauthorized IP addresses that send IP configuration parameters.
    Affected if Unauthorized or unexpected CIP connections are observed attempting to modify IP configuration, or IP configuration has changed without authorized administrative action.
  5. Compare current IP configuration to baseline
    Document the expected IP address, subnet mask, and gateway for the affected device. Verify the current IP settings match the baseline by pinging the device, checking DHCP/BootP logs, or reviewing switch ARP tables.
    Affected if The device IP address, subnet, or gateway has changed without authorized configuration, indicating possible exploitation.

A user is affected if they have any of the listed MicroLogix 1400 or 1756 communication modules on their network with CIP enabled and accepting IP configuration changes, especially if unauthorized IP change attempts are detected or the IP has unexpectedly changed.

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 10.10
Interim mitigation

Implement network segmentation and firewall rules to restrict CIP traffic to authorized sources only, and apply vendor firmware updates when available. Consider disabling CIP-based IP configuration or implementing network monitoring for unexpected IP changes.

Fix this in Micrologix 1400 Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
27.0 hours of engineering $4,800
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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-2018-17924 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
  • 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