CVE-2020-6998
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 · uneditedThe connection establishment algorithm found in Rockwell Automation CompactLogix 5370 and ControlLogix 5570 versions 33 and prior does not sufficiently manage its control flow during execution, creating an infinite loop. This may allow an attacker to send specially crafted CIP packet requests to a controller, which may cause denial-of-service conditions in communications with other products.
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 confidenceRockwell Automation CompactLogix 5370 and ControlLogix 5570 controllers versions 33 and prior contain a vulnerability in the connection establishment algorithm where insufficient control flow management creates an infinite loop condition. An attacker sending specially crafted CIP (Common Industrial Protocol) packets can trigger this infinite loop, causing denial-of-service conditions that disrupt communications with the controller and other connected products.
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<= 33<= 33<= 33<= 33<= 33<= 33<= 33<= 33CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify Rockwell controllers on the networkUse network scanning tools (such as RSLinx, FactoryTalk, or third-party industrial network scanners) to discover CompactLogix 5370, ControlLogix 5570, or Guardlogix controllers. Check your asset inventory or engineering workstation configurations for these controller models.Affected if Any CompactLogix 5370 (any L1/L2/L3 variant), ControlLogix 5570, Guardlogix 5560, Guardlogix 5570, or Armor Compact Guardlogix 5370 controllers are present in the environment.
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Check controller firmware versionConnect to the controller via RSLinx Classic or FactoryTalk Linx, then use RSLogix 5000/Studio 5000 to view the controller properties, or access the controller's built-in web server if available. The firmware version is displayed in the controller properties or system information screen.Affected if The controller firmware version is 33 or lower.
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Verify network exposure of CIP portsCheck firewall rules and network segmentation to determine if CIP traffic on port 44818 (EtherNet/IP) and port 2222 (CIP Safety) is accessible from untrusted networks. Review network diagrams and firewall configurations to identify exposed attack surfaces.Affected if CIP ports are accessible from networks outside the trusted industrial automation zone without filtering.
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Review CIP connection traffic patternsMonitor network traffic using an industrial protocol analyzer (like Wireshark with EtherNet/IP dissector) or intrusion detection system for CIP connection establishment packets. Look for abnormal connection attempts or unusual patterns in CIP session initialization.Affected if Unusual or malformed CIP connection packets are observed, or controller becomes unresponsive during connection attempts from specific sources.
You are affected if you have any CompactLogix 5370, ControlLogix 5570, Guardlogix 5560, Guardlogix 5570, or Armor Compact Guardlogix 5370 controllers running firmware version 33 or lower that have CIP network access.
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 dataUpdate affected controllers to firmware version 34 or later. If immediate patching is not feasible, implement network segmentation and firewall rules to restrict CIP traffic to authorized sources only, and monitor for signs of DoS conditions.
- Consultation8.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-6998 — 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-2020-6998 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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