ICS Advisory (ICSA-21-068-04)

Siemens SINEMA Remote Connect Server

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1. EXECUTIVE SUMMARY

  • CVSS v3 8.8
  • ATTENTION: Exploitable remotely/low skill level to exploit
  • Vendor: Siemens 
  • Equipment: SINEMA Remote Connect Server
  • Vulnerabilities: Incorrect Authorization\

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow authenticated unprivileged user accounts to access unauthorized functionality.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of SINEMA Remote Connect Server are affected:

  • SINEMA Remote Connect Server: All versions prior to v3.0

3.2 VULNERABILITY OVERVIEW

3.2.1    INCORRECT AUTHORIZATION CWE-863

The webserver could allow unauthorized actions via special URLs for unprivileged users. The settings of the Unified Management Component (UMC) authorization server could be changed to add a rogue server by an attacker authenticating with unprivileged user rights. 

CVE-2020-25239 has been assigned to this vulnerability. A CVSS v3 base score of 8.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

3.2.2    INCORRECT AUTHORIZATION CWE-863

Unprivileged users can access services when guessing the URL. An attacker could impact availability, integrity, and gain information from logs and templates of the service. 

CVE-2020-25240 has been assigned to this vulnerability. A CVSS v3 base score of 6.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L).

3.3 BACKGROUND

  • CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
  • COUNTRIES/AREAS DEPLOYED: Worldwide
  • COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Siemens reported these vulnerabilities to CISA.

4. MITIGATIONS

Siemens recommends updating to v3.0 or later and has identified the following specific workarounds and mitigations that customers can apply to reduce risk:

  • Check that all settings are as expected when applying templates.
  • Configure a syslog server for logs.
  • Ensure all accounts (including unprivileged) are trusted.

As a general security measure, Siemens strongly recommends protecting network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens’ operational guidelines for industrial security, and to follow the recommendations in the product manuals. 

Additional information on industrial security by Siemens can be found at: https://www.siemens.com/industrialsecurity

For more information refer to Siemens security advisory SSA-731317

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

CISA also provides a section for control systems security recommended practices on the ICS webpage on us-cert.cisa.gov. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available on the ICS webpage on us-cert.cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to CISA for tracking and correlation against other incidents.

No known public exploits specifically target these vulnerabilities.


Contact Information

For any questions related to this report, please contact the CISA at:

Email: CISAservicedesk@cisa.dhs.gov
Toll Free: 1-888-282-0870

For industrial control systems cybersecurity information:  https://us-cert.cisa.gov/ics 
or incident reporting:  https://us-cert.cisa.gov/report

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