CVE-2020-25242
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 SIMATIC NET CP 343-1 Advanced (incl. SIPLUS variants) (All versions), SIMATIC NET CP 343-1 Lean (incl. SIPLUS variants) (All versions), SIMATIC NET CP 343-1 Standard (incl. SIPLUS variants) (All versions). Specially crafted packets sent to TCP port 102 could cause a Denial-of-Service condition on the affected devices. A cold restart might be necessary in order to recover.
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 confidenceThis is a Denial of Service vulnerability in Siemens SIMATIC NET CP 343-1 industrial communication processors (Advanced, Lean, and Standard variants). Specially crafted packets sent to TCP port 102 (S7comm protocol for PLC communication) can cause the affected device to become unresponsive, with recovery requiring a cold restart.
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 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 SIMATIC NET CP 343-1 devices on the networkReview network inventory, scan for Siemens S7comm devices, or physically inspect industrial network equipment for CP 343-1 modules (Advanced, Lean, or Standard variants)Affected if The environment contains any SIMATIC NET CP 343-1 device in Advanced, Lean, or Standard variant
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Confirm device firmware versionAccess the device web interface, use TIA Portal, or check device firmware via Siemens management tools; compare against the 'all versions' affected range stated in the CVEAffected if Any firmware version is present, since all versions are affected
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Check TCP port 102 exposurePerform a port scan of network segments where CP 343-1 devices reside, looking for open TCP port 102 (S7comm)Affected if TCP port 102 is accessible from untrusted or external network segments
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Verify network segmentationReview firewall rules, VLAN configurations, or access control lists protecting the industrial network where CP 343-1 devices are deployedAffected if No firewall rules or segmentation exist between untrusted networks and the device's TCP port 102
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Test device responsivenessPing the device or attempt S7comm communication to TCP port 102 to verify the device is currently operationalAffected if The device does not respond to S7comm queries, indicating a potential DoS condition from this or another vulnerability
The environment is affected if any SIMATIC NET CP 343-1 device (Advanced, Lean, or Standard) with TCP port 102 accessible from untrusted networks is present, since all firmware versions are vulnerable.
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 dataApply network segmentation and firewall rules to restrict unauthorized access to TCP port 102; consult Siemens for available firmware updates as no patch is explicitly mentioned for 'all versions' of these products.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA3.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-25242 — 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-2020-25242 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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