Sinema Remote Connect ServerApplication · Siemens

CVE-2020-25239

HIGH · 8.8 CVSS v3.1 Published 2021-03-15
Fix available
A fix is available. Upgrade to 3.0 or later.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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 SINEMA Remote Connect Server (All versions < V3.0). The webserver could allow unauthorized actions via special urls for unpriviledged users. The settings of the UMC authorization server could be changed to add a rogue server by an attacker authenticating with unprivilege user rights.

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

This is an authorization bypass vulnerability in SINEMA Remote Connect Server's webserver. Unprivileged users can access special URLs to perform unauthorized actions, including modifying UMC (User Management Component) authorization server settings to add a rogue server. This represents a privilege escalation issue where authenticated unprivileged users can inject malicious authorization servers into the trusted configuration.

MitigationUpgrade SINEMA Remote Connect Server to version V3.0 or later to remediate this vulnerability. If immediate upgrade is not feasible, restrict network access to the webserver and monitor UMC configuration changes for signs of unauthorized modification.

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
Sinema Remote Connect ServerApplication
Affected:< 3.0

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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 checks

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

  1. Identify SINEMA Remote Connect Server installation
    Locate the SINEMA Remote Connect Server installation on the system. Check for the Siemens installation directory, typically under C:\Program Files\Siemens\SINEMA Remote Connect Server or /opt/siemens/sinema-rc-server. Verify the product name matches 'SINEMA Remote Connect Server' or 'SINEMA RC Server'.
    Affected if The product is installed and is Siemens Sinema Remote Connect Server.
  2. Determine installed version
    Open the SINEMA Remote Connect Server management interface or check the installation directory for version information. Common locations include the About section in the web UI, the README file, or the installed package metadata. Compare the version number against the affected range.
    Affected if The installed version is any version prior to V3.0 (for example, V2.x, V1.x).
  3. Verify webserver is accessible
    Confirm the SINEMA Remote Connect Server web interface is running and accessible on the configured port (typically 443 or 8443). Use a browser or curl to attempt access to the login page.
    Affected if The webserver is running and network-accessible (even locally).
  4. Inspect UMC authorization server configuration
    Access the UMC (User Management Component) configuration panel within the SINEMA Remote Connect Server web interface. Navigate to the authorization server settings section. Review the list of configured authorization servers for any unrecognized or rogue servers that were not added by an administrator.
    Affected if The UMC configuration shows authorization servers that were not intentionally added by legitimate administrators, or changes to authorization server settings are observed that were not initiated by an authorized admin.
  5. Review access logs for unauthorized URL patterns
    Examine the SINEMA Remote Connect Server access and audit logs, typically found in the logs directory of the installation. Search for requests to special or administrative URLs that may indicate privilege escalation attempts, especially those from unprivileged user accounts.
    Affected if Logs contain requests to administrative or configuration URLs made by users who should not have such privileges, particularly those modifying UMC or authorization server settings.

You are affected if SINEMA Remote Connect Server is installed with a version prior to V3.0 and the webserver is accessible, as unprivileged users could have exploited the authorization bypass to inject malicious authorization servers into the UMC configuration.

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.

dbcve · scoped
Upgrade available Upgrade to 3.0 or later
Fixed in 3.0
Interim mitigation

Upgrade SINEMA Remote Connect Server to version V3.0 or later to remediate this vulnerability. If immediate upgrade is not feasible, restrict network access to the webserver and monitor UMC configuration changes for signs of unauthorized modification.

Recommended fix High confidence

Sinema Remote Connect Server V3.0

  1. Backup the current Sinema Remote Connect Server configuration and database
  2. Ensure the system meets the hardware requirements for V3.0
  3. Download Sinema Remote Connect Server V3.0 or later from the Siemens Industry Online Support portal (https://support.industry.siemens.com)
  4. Stop all Sinema Remote Connect Server services
  5. Install Sinema Remote Connect Server V3.0 using the installer
  6. After installation, verify the UMC authorization server settings to ensure no rogue servers were added
  7. Restart the Sinema Remote Connect Server services
  8. Confirm the web interface is accessible and verify authorization controls are functioning correctly
Caveat Review Siemens release notes for V3.0 for any configuration or feature changes that may require adjustment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Sinema Remote Connect Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2020-25239 in production — separate from our analysis above.

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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
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  • No spam, self-promotion, credentials, or personal data