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Simatic S7 400 FirmwareOperating system · Siemens

CVE-2018-16557

HIGH · 8.2 CVSS v3.1 Published 2018-12-13
Fix available
A fix is available. Upgrade to 6.0.9 / 8.2.1 or later.
See remediation →
91/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
A vulnerability has been identified in SIMATIC S7-400 CPU 412-1 DP V7 (All versions), SIMATIC S7-400 CPU 412-2 DP V7 (All versions), SIMATIC S7-400 CPU 414-2 DP V7 (All versions), SIMATIC S7-400 CPU 414-3 DP V7 (All versions), SIMATIC S7-400 CPU 414-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 414F-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 416-2 DP V7 (All versions), SIMATIC S7-400 CPU 416-3 DP V7 (All versions), SIMATIC S7-400 CPU 416-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 416F-2 DP V7 (All versions), SIMATIC S7-400 CPU 416F-3 PN/DP V7 (All versions < V7.0.3), SIMATIC S7-400 CPU 417-4 DP V7 (All versions), SIMATIC S7-400 CPU 412-2 PN V7 (All versions < V7.0.3), SIMATIC S7-400 H V4.5 and below CPU family (incl. SIPLUS variants) (All versions), SIMATIC S7-400 H V6 CPU family (incl. SIPLUS variants) (All versions < V6.0.9), SIMATIC S7-400 PN/DP V6 and below CPU family (incl. SIPLUS variants) (All versions), SIMATIC S7-410 CPU family (incl. SIPLUS variants) (All versions < V8.2.1), SIPLUS S7-400 CPU 414-3 PN/DP V7 (All versions < V7.0.3), SIPLUS S7-400 CPU 416-3 PN/DP V7 (All versions < V7.0.3), SIPLUS S7-400 CPU 416-3 V7 (All versions), SIPLUS S7-400 CPU 417-4 V7 (All versions). Sending of specially crafted packets to port 102/tcp via Ethernet interface via PROFIBUS or Multi Point Interfaces (MPI) could cause a denial of service condition on affected devices. Flashing with a firmware image may be required to recover the CPU. Successful exploitation requires an attacker to have network access to port 102/tcp via Ethernet interface or to be able to send messages via PROFIBUS or Multi Point Interfaces (MPI) to the device. No user interaction is required. If no access protection is configured, no privileges are required to exploit the security vulnerability. The vulnerability could allow causing a denial of service condition of the core functionality of the CPU, compromising the availability of the 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 confidence

Denial of service vulnerability in Siemens SIMATIC S7-400 CPU family allowing remote attackers to crash affected devices by sending specially crafted packets to port 102/tcp via Ethernet, PROFIBUS, or MPI interfaces. Successful exploitation causes CPU failure requiring firmware reflash for recovery.

MitigationApply vendor-supplied firmware updates to all affected S7-400 CPU models; implement network segmentation and access controls on port 102/tcp to limit exposure.

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
Simatic S7 400 FirmwareOperating system
Affected:<= v6.0
Simatic S7 400 Pn\/dp V7 FirmwareOperating system
Affected:all versions
Simatic S7 400h FirmwareOperating system
Affected:<= v4.5>= 6.0.0, < 6.0.9
Simatic S7 410 FirmwareOperating system
Affected:< 8.2.1

CVSS 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
Low
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the SIMATIC S7 CPU model
    Access the PLC via TIA Portal, STEP 7, or the device's web interface to confirm the exact CPU model (S7-400, S7-400 Pn/dp V7, S7-400h, or S7-410)
    Affected if The device is any of these four S7-400 family models
  2. Determine the installed firmware version
    In TIA Portal or STEP 7, go to the CPU's Online & Diagnostics > General > Firmware version; or access the device's diagnostics buffer or web interface
    Affected if Firmware version is <=6.0 for S7-400, any version for S7-400 Pn/dp V7, <=4.5 or >=6.0.0 but <6.0.9 for S7-400h, or <8.2.1 for S7-410
  3. Verify port 102/tcp exposure
    Scan the network for open port 102/tcp on the PLC's IP address using a port scanner (e.g., nmap -p 102 <target_ip>)
    Affected if Port 102/tcp is accessible from untrusted networks
  4. Confirm enabled industrial interfaces
    In TIA Portal/STEP 7, check the CPU's properties for enabled communication interfaces: Ethernet (PN), PROFIBUS (DP), or MPI
    Affected if Any of these interfaces are enabled and reachable on the network

A user is affected if they have an S7-400 family CPU with firmware matching the vulnerable versions AND port 102/tcp is network-accessible with an enabled interface.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to 6.0.9 / 8.2.1 or later
Fixed in 6.0.98.2.1
Interim mitigation

Apply vendor-supplied firmware updates to all affected S7-400 CPU models; implement network segmentation and access controls on port 102/tcp to limit exposure.

Fix this in Simatic S7 400 Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,380
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-16557 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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