CVE-2018-4854
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 · uneditedA vulnerability has been identified in SICLOCK TC100 (All versions) and SICLOCK TC400 (All versions). An attacker with network access to port 69/udp could modify the administrative client stored on the device. If a legitimate user downloads and executes the modified client from the affected device, then he/she could obtain code execution on the client system.
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 confidenceThe SICLOCK TC100 and TC400 devices expose an administrative client download via TFTP on port 69/UDP without authentication or encryption. An attacker with network access to this port can perform a man-in-the-middle attack to modify the client software stored on the device. When legitimate administrators download and execute this trojanized client, the attacker gains code execution on the administrator's system.
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
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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 SICLOCK devices on the networkPerform network discovery (e.g., nmap, network scans) to locate devices with vendor fingerprint matching Siemens SICLOCK TC100 or TC400. Check device HTTP management interfaces or SNMP for device identification strings.Affected if The device is a Siemens SICLOCK TC100 or TC400 with any firmware version.
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Verify TFTP service exposureScan the identified device for open port 69/UDP using: nmap -sU -p 69 <target_ip> or similar UDP port scanner.Affected if Port 69/UDP is open and responding on the SICLOCK device.
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Confirm network accessibility from untrusted segmentsDetermine if port 69/UDP is reachable from network segments that contain untrusted or non-administrative systems. Check firewall rules, ACLs, or VLAN membership affecting the device.Affected if The TFTP service on the device is accessible from network segments outside the trusted administrator network.
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Check for client download integrity mechanismsIf TFTP access is confirmed, examine whether the device provides or requires checksum verification for downloaded client software, or whether the TFTP service supports any authentication mechanisms.Affected if The TFTP service allows unauthenticated downloads with no integrity verification mechanism present.
A user is affected if they have a Siemens SICLOCK TC100 or TC400 device with TFTP port 69/UDP exposed to untrusted networks, enabling potential man-in-the-middle attacks on administrative client downloads.
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 port 69/UDP through firewall rules or network segmentation to limit exposure to trusted administrators only. Implement integrity verification (e.g., checksums) for any downloaded client software, and consider isolating affected devices on a dedicated VLAN.
- 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-2018-4854 — 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-2018-4854 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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