CVE-2012-6439
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 · uneditedWhen an affected product receives a valid CIP message from an unauthorized or unintended source to Port 2222/TCP, Port 2222/UDP, Port 44818/TCP, or Port 44818/UDP that changes the product’s configuration and network parameters, a DoS condition can occur. This situation could cause loss of availability and a disruption of communication with other connected devices. Rockwell Automation EtherNet/IP products; 1756-ENBT, 1756-EWEB, 1768-ENBT, and 1768-EWEB communication modules; CompactLogix L32E and L35E controllers; 1788-ENBT FLEXLogix adapter; 1794-AENTR FLEX I/O EtherNet/IP adapter; ControlLogix 18 and earlier; CompactLogix 18 and earlier; GuardLogix 18 and earlier; SoftLogix 18 and earlier; CompactLogix controllers 19 and earlier; SoftLogix controllers 19 and earlier; ControlLogix controllers 20 and earlier; GuardLogix controllers 20 and earlier; and MicroLogix 1100 and 1400
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 confidenceA denial of service vulnerability exists in Rockwell Automation EtherNet/IP products where valid CIP (Common Industrial Protocol) messages received on ports 2222/TCP, 2222/UDP, 44818/TCP, or 44818/UDP from unauthorized or unintended sources can alter the device's configuration and network parameters, causing the device to become unavailable and disrupting communication with other connected devices.
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<= 20<= 20<= 1100<= 1400<= 19all versionsall versionsall versionsall versionsCVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- Partial
- Availability
- Complete
AV:N/AC:L/Au:N/C:N/I:P/A:C
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 checksWork through these to decide whether this CVE applies to you.
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Identify the Rockwell EtherNet/IP device on the networkLocate the device's model number and type (Controllogix, Guardlogix, Micrologix, Softlogix, or 1756/1768 ENBT/EWEB) through physical inspection, network documentation, or by querying the device via RSLinx or similar OPC client tools.Affected if The device is one of: Controllogix, Guardlogix, Micrologix (1100 or 1400), Softlogix, 1756-ENBT, 1756-EWEB, 1768-ENBT, or 1768-EWEB.
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Determine the firmware versionConnect to the device via RSLinx Classic or Studio 5000 Logix Designer and navigate to the Controller Properties or Device Properties to read the firmware revision. For ENBT/EWEB modules, check the module's electronic keying or properties in the I/O configuration tree.Affected if The firmware version is at or below 20 for Controllogix/Guardlogix, at or below 19 for Softlogix, at or below 1100 or 1400 for Micrologix, or any version for 1756-ENBT, 1756-EWEB, 1768-ENBT, or 1768-EWEB.
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Verify network exposure of vulnerable portsPerform a port scan or check firewall rules to determine if ports 2222/TCP, 2222/UDP, 44818/TCP, and 44818/UDP are open and accessible from unauthorized network segments. Use tools like nmap: 'nmap -p 2222,44818 -sTU <device_ip>'Affected if Any of these ports (2222 or 44818, TCP or UDP) are accessible from network segments that contain untrusted or unauthorized hosts.
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Confirm if network segmentation is in placeReview firewall rules, VLAN configurations, or ACLs to verify whether the device's EtherNet/IP ports are restricted to only trusted engineering workstations or control network segments.Affected if No firewall, VLAN, or ACL restrictions exist to limit access to ports 2222 and 44818 to authorized management stations only.
The environment is affected if the device is one of the listed Rockwell Automation products with a firmware version within the affected ranges, AND ports 2222 or 44818 are accessible from untrusted network segments without proper access controls.
Generated from the published advisory. Verify against your own configuration.
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 dataRestrict network access to ports 2222 and 44818 using firewalls or network segmentation to prevent unauthorized CIP messages from reaching affected devices. Apply vendor-provided firmware updates as they become available.
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2012-6439 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2012-6439 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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