CVE-2018-5400
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 Auto-Maskin products utilize an undocumented custom protocol to set up Modbus communications with other devices without validating those devices. The originating device sends a message in plaintext, 48:65:6c:6c:6f:20:57:6f:72:6c:64, "Hello World" over UDP ports 44444-44446 to the broadcast address for the LAN. Without verification devices respond to any of these broadcast messages on the LAN with a plaintext reply over UDP containing the device model and firmware version. Following this exchange the devices allow Modbus transmissions between the two devices on the standard Modbus port 502 TCP. Impact: An attacker can exploit this vulnerability to send arbitrary messages to any DCU or RP device through spoofing or replay attacks as long as they have access to the network. Affected releases are Auto-Maskin DCU-210E RP-210E: Versions prior to 3.7 on ARMv7.
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 confidenceAuto-Maskin DCU-210E and RP-210E devices use an undocumented plaintext protocol broadcasting 'Hello World' messages over UDP ports 44444-444446. Any device on the LAN can respond with device model/firmware version, after which Modbus TCP communication on port 502 is allowed between the devices. This enables attackers to spoof or replay broadcast messages to inject arbitrary Modbus commands to vulnerable 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 dataall 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
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
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 Auto-Maskin DCU-210E or RP-210E devices on the networkScan the network for devices responding to UDP probes on ports 44444, 444445, or 444446. Send a plaintext 'Hello World' message to these ports and look for responses containing device model and firmware version strings.Affected if Devices matching Auto-Maskin DCU-210E or RP-210E models respond to the Hello World probe on UDP ports 44444-444446.
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Check firmware version of identified Auto-Maskin devicesQuery the device for its firmware version via the Hello World protocol response or via Modbus TCP on port 502. Compare the version string against the fixed version 3.7 on ARMv7.Affected if The device firmware version is earlier than 3.7, or the version cannot be determined (all versions prior to 3.7 are affected).
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Verify UDP ports 44444-444446 are exposedPerform a UDP port scan of suspected device IP addresses on ports 44444, 444445, and 444446. Confirm these ports are listening and accessible.Affected if UDP ports 44444, 444445, or 444446 are open and reachable from an untrusted network segment.
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Verify Modbus TCP port 502 is network-accessiblePerform a TCP port scan on port 502 against the Auto-Maskin device IP addresses. Confirm whether port 502 accepts connections from untrusted network segments.Affected if Modbus TCP port 502 is accessible from an untrusted or unmanaged network segment.
A defender is affected if Auto-Maskin DCU-210E or RP-210E devices with firmware versions earlier than 3.7 are present and their UDP discovery ports (44444-444446) or Modbus TCP port 502 are reachable from an untrusted network segment.
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.
dbcve · scopedUpgrade affected devices to firmware version 3.7 or later on ARMv7. Additionally, implement network segmentation to isolate ICS devices and add authentication/verification for Modbus communications.
Firmware version 3.7 on ARMv7
- Identify all DCU-210E and RP-210E devices on the network running firmware versions prior to 3.7 on ARMv7
- Verify the current firmware version of each affected device
- Obtain the official firmware version 3.7 for ARMv7 from Auto-Maskin
- Apply the firmware upgrade to each affected device following the vendor's official upgrade procedure
- After upgrading, verify that devices are running firmware version 3.7 or later
- Confirm that the devices no longer respond to unauthenticated broadcast messages on UDP ports 44444-44446
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-5400 — 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-2018-5400 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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