ICS Advisory (ICSA-21-159-13)

Siemens SIMATIC RFID

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1. EXECUTIVE SUMMARY

  • CVSS v3 7.5
  • ATTENTION: Low attack complexity
  • Vendor: Siemens
  • Equipment: SIMATIC RF Products
  • Vulnerability: Uncontrolled Resource Consumption

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an unauthorized attacker to crash the OPC UA service of the affected devices.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

  • The following versions of SIMATIC RF are affected:
  • SIMATIC RF166C, all versions between v1.1 and v1.3.2
  • SIMATIC RF185C, all versions between v1.1 and v1.3.2
  • SIMATIC RF186C, all versions between v1.1 and v1.3.2
  • SIMATIC RF186CI, all versions between v1.1 and v1.3.2
  • SIMATIC RF188C, all versions between v1.1 and v1.3.2
  • SIMATIC RF188CI, all versions between v1.1 and v1.3.2
  • SIMATIC RF360R, all versions
  • SIMATIC RF615R, all versions prior v3.0
  • SIMATIC RF680R all versions prior to v3.0
  • SIMATIC RF685R, all versions prior to v3.0

3.2 VULNERABILITY OVERVIEW

3.2.1    UNCONTROLLED RESOURCE CONSUMPTION CWE-400

Affected devices do not properly handle large numbers of incoming connections. An attacker may leverage this to cause a denial-of-service condition.

CVE-2021-31340 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.3 BACKGROUND

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

3.4 RESEARCHER

Siemens reported this vulnerability to CISA.

4. MITIGATIONS

Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:

  • Update to v1.3.2 where applicable
  • Deactivate the OPC-UA feature of affected devices

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

For more information see Siemens Security Advisory SSA-787292

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:

  • Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
  • Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
  • When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as its connected devices.

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 this vulnerability. This vulnerability is not exploitable remotely.


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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