1. EXECUTIVE SUMMARY

  • CVSS v3 7.5
  • ATTENTION: Exploitable remotely/low skill level to exploit
  • Vendor: Siemens
  • Equipment: SINAMICS PERFECT HARMONY GH180 Drives NXG I and NXG II
  • Vulnerability: Uncontrolled Resource Consumption

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker with access to the Ethernet Modbus Interface to cause a denial-of-service condition exceeding the number of available connections.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following SINAMICS PERFECT HARMONY GH180 products are affected:

  • SINAMICS PERFECT HARMONY GH180 with NXG I control, MLFBs: 6SR2. . . -, 6SR3. . . -, 6SR4. . . -: All versions with option G28
  • SINAMICS PERFECT HARMONY GH180 with NXG II control, MLFBs: 6SR2. . . -, 6SR3. . . -, 6SR4. . . -: All versions with option G28

3.2 VULNERABILITY OVERVIEW

3.2.1    UNCONTROLLED RESOURCE CONSUMPTION CWE-400

Successful exploitation requires no privileges and no user interaction. An attacker with network access to the device could use the vulnerability to compromise availability of the affected system.

CVE-2019-6578 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; 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: Chemical, Energy, Food and Agriculture, Healthcare and Public Health, Transportation Systems, Water and Wastewater Systems
  • COUNTRIES/AREAS DEPLOYED: Worldwide
  • COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Siemens reported this vulnerability to NCCIC.

4. MITIGATIONS

Siemens recommends that affected users upgrade to NXGpro control. Please contact Siemens’ customer service to obtain and install the upgrade.

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

  • Install a protocol bridge that isolates the networks and eliminates direct connections to the Ethernet Modbus Interface.
  • Apply cell protection concept and implement defense in depth.

For more information see Siemens advisory SSA-606525 located at:

https://www.siemens.com/cert/advisories

NCCIC 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 that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the connected devices.

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

NCCIC also provides a section for control systems security recommended practices on the ICS-CERT web page. 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-CERT website 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 NCCIC for tracking and correlation against other incidents.

No known public exploits specifically target this vulnerability.

 

Source:

https://ics-cert.us-cert.gov/advisories/ICSA-19-134-05