CVE-2016-4784
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 firmware variant PROFINET IO for EN100 Ethernet module : All versions < V1.04.01; Firmware variant Modbus TCP for EN100 Ethernet module : All versions < V1.11.00; Firmware variant DNP3 TCP for EN100 Ethernet module : All versions < V1.03; Firmware variant IEC 104 for EN100 Ethernet module : All versions < V1.21; EN100 Ethernet module included in SIPROTEC Merging Unit 6MU80 : All versions < 1.02.02; SIPROTEC 7SJ686 : All versions < V 4.83; SIPROTEC 7UT686 : All versions < V 4.01; SIPROTEC 7SD686 : All versions < V 4.03; SIPROTEC 7SJ66 : All versions < V 4.20. The integrated web server (port 80/tcp) of the affected devices could allow remote attackers to obtain sensitive device information if network access was obtained.
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 integrated web server on port 80/tcp in Siemens EN100 Ethernet modules and SIPROTEC devices exposes sensitive device information to remote attackers who obtain network access. This information disclosure vulnerability affects multiple firmware variants (PROFINET IO, Modbus TCP, DNP3 TCP, IEC 104) across several SIPROTEC protection relay models without requiring authentication.
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 versions= 4.26CVSS 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
- Low
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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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Verify port 80/tcp is listening on the deviceRun a network port scan (e.g., nmap -p 80 <device_ip> or netstat -an | grep :80) to confirm the web server port is open and accepting connectionsAffected if Port 80/tcp is open and responding on the EN100 module or SIPROTEC device
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Identify the device model and firmware versionAccess the web interface on port 80 or use SNMP/siemens management tools to query the device firmware version and model (EN100 variant or SIPROTEC model number)Affected if Device is an EN100 Ethernet module or SIPROTEC protection relay running firmware version 4.26 or earlier, or any version if the web server is enabled
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Confirm web server requires no authenticationAttempt to access common web paths (e.g., /, /home, /status) on port 80 without providing credentials to verify if sensitive device information is returned anonymouslyAffected if The web server returns sensitive device configuration, network details, or operational data without requiring any login credentials
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Check for sensitive information exposureReview the HTTP response from port 80 for exposed details such as device configuration, firmware version, network settings, or relay parameters that should be restrictedAffected if The web interface exposes sensitive device information including configuration data, firmware details, network parameters, or operational status to unauthenticated remote attackers
The device is affected if port 80/tcp is open on a Siemens EN100 Ethernet module or SIPROTEC device and the web server returns sensitive device information without requiring authentication.
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 firmware for each affected variant to the specified minimum versions (PROFINET IO: V1.04.01, Modbus TCP: V1.11.00, DNP3 TCP: V1.03, IEC 104: V1.21, 6MU80: 1.02.02, 7SJ686: V4.83, 7UT686: V4.01, 7SD686: V4.03, 7SJ66: V4.20). If updates cannot be applied immediately, disable the web server on port 80/tcp or isolate affected devices behind a firewall.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-4784 — 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-2016-4784 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
- No weaponised exploit code, or anything meant to cause harm
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