Active Opc ServerOperating system · Moxa

CVE-2016-5793

HIGH · 8.8 CVSS v3.0 Published 2016-09-24
Fix available
A fix is available. Upgrade to after 2.4.18 or later.
See remediation →
90/100
Remediation priority · Urgent
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
Unquoted Windows search path vulnerability in Moxa Active OPC Server before 2.4.19 allows local users to gain privileges via a Trojan horse executable file in the %SYSTEMDRIVE% directory.

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

Moxa Active OPC Server versions prior to 2.4.19 contain an unquoted Windows service path vulnerability. The service executable path contains spaces and is not enclosed in quotes, causing Windows to search for and execute malicious executables placed in the %SYSTEMDRIVE% directory (e.g., C:\) when the service starts. Local users can exploit this to gain elevated privileges by placing a Trojan horse executable with a name that matches an intermediate path component.

MitigationUpgrade Moxa Active OPC Server to version 2.4.19 or later, which contains the vendor fix for this vulnerability.

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
Active Opc ServerOperating system
Affected:<= 2.4.18

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/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 checks

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

  1. Check if Moxa Active OPC Server is installed
    Open Programs and Features (appwiz.cpl) or check the default installation directory C:\Program Files\Moxa\ActiveOPCServer for the presence of the software
    Affected if Moxa Active OPC Server appears in installed programs or the installation directory exists
  2. Identify the installed version
    Right-click on the Moxa Active OPC Server entry in Programs and Features and select Properties, or check the version info of the main executable file in the installation directory
    Affected if The version shown is 2.4.18 or lower
  3. Locate the Windows service entry
    Open Services (services.msc) and look for a service containing 'ActiveOPC' or 'Moxa Active OPC' in the name, or run 'sc queryex type= service state= all' and search for the service name
    Affected if A Windows service associated with Moxa Active OPC Server is found
  4. Inspect the service executable path for quotes
    Run 'sc qc <service_name>' from command prompt or check the ImagePath value in registry under HKLM\SYSTEM\CurrentControlSet\Services\<service_name>
    Affected if The BINARY_PATH_VALUE or ImagePath contains spaces and is not enclosed in double quotes (e.g., C:\Program Files\Moxa\ActiveOPCServer\server.exe instead of "C:\Program Files\Moxa\ActiveOPCServer\server.exe")
  5. Confirm version is within affected range
    If version cannot be directly determined, compare the installed build against the fixed version 2.4.19
    Affected if Running version 2.4.18 or any version prior to 2.4.19

A user is affected if Moxa Active OPC Server version 2.4.18 or lower is installed AND the service's executable path contains spaces without being enclosed in quotes.

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 a release after 2.4.18
Interim mitigation

Upgrade Moxa Active OPC Server to version 2.4.19 or later, which contains the vendor fix for this vulnerability.

Fix this in Active Opc Server Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,424.

Scan for this in your stack

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dbcve dependency scanner

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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-2016-5793 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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