1. EXECUTIVE SUMMARY

  • CVSS v3 7.5
  • ATTENTION: Exploitable remotely/low skill level to exploit.
  • Vendor: Siemens
  • Equipment: SIMATIC PCS 7, SIMATIC WinCC, SIMATIC WinCC Runtime Professional, and SIMATIC NET PC Software
  • Vulnerability: Improper Input Validation

2. UPDATE INFORMATION

This updated advisory is a follow-up to the updated advisory titled ICSA-18-088-03 Siemens SIMATIC PCS 7, SIMATIC WinCC, SIMATIC WinCC Runtime Professional, and SIMATIC NET PC Software (Update C) that was published October 9, 2018, on the NCCIC/ICS-CERT website.

3. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to cause a denial-of-service condition on the remote and local communication functionality of the affected products. A system reboot is required to recover.

4. TECHNICAL DETAILS

4.1 AFFECTED PRODUCTS

Siemens reports that the vulnerability affects the following SIMATIC products:

  • OpenPCS 7 v7.1 and earlier,
  • OpenPCS 7 v8.0: All versions prior to 8.2 SP1,
  • OpenPCS 7 v8.1: All versions,
  • OpenPCS 7 v8.2: All versions,
  • OpenPCS 7 v9.0: All versions prior to v9.0 Upd1,
  • SIMATIC BATCH v7.1 and earlier,
  • SIMATIC BATCH v8.0: All versions prior to v8.0 SP1 Upd21,
  • SIMATIC BATCH v8.1: All versions prior to v8.1 SP1 Upd16,
  • SIMATIC BATCH v8.2: All versions,
  • SIMATIC BATCH v9.0: All versions prior to v9.0 SP1,
  • SIMATIC NET PC-Software: All versions,
  • SIMATIC PCS 7 v7.1 and earlier,
  • SIMATIC PCS 7 v8.0: All versions,
  • SIMATIC PCS 7 v8.1: All versions,
  • SIMATIC PCS 7 v8.2: All versions,
  • SIMATIC PCS 7 v9.0: All versions prior to v9.0 SP1,
  • SIMATIC Route Control v7.1 and earlier,
  • SIMATIC Route Control v8.0: All versions,
  • SIMATIC Route Control v8.1: All versions,
  • SIMATIC Route Control v8.2: All versions,
  • SIMATIC Route Control v9.0: All versions prior to v9.0 Upd1,
  • SIMATIC WinCC Runtime Professional: All versions prior to v14 SP1 Upd5,
  • SIMATIC WinCC 7.2 and earlier,
  • SIMATIC WinCC 7.3: All versions prior to WinCC 7.3 Upd16, and
  • SIMATIC WinCC 7.4: All versions prior to v7.4 SP1 Upd4
——— Begin Update D Part 1 of 2 ——–
  • SIMATIC BATCH v8.2: All versions prior to v8.2 Upd10, and
  • SIMATIC PCS 7 v8.2: All versions prior to v8.2 SP1,

——— End Update D Part 1 of 2 ———-

4.2 VULNERABILITY OVERVIEW

4.2.1 IMPROPER INPUT VALIDATION CWE-20

Specially crafted messages sent to the RPC service of the affected products could cause a denial-of-service condition on the remote and local communication functionality of the affected products. A reboot of the system is required to recover the remote and local communication functionality.

CVE-2018-4832 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).

4.3 BACKGROUND

  • Critical Infrastructure Sectors: Chemical, Energy, Food and Agriculture, Water and Wastewater Systems.
  • Countries/Areas Deployed: Worldwide
  • Company Headquarters Location: Germany

4.4 RESEARCHER

Vladimir Dashchenko from Kaspersky Lab and independent researcher cdev1 reported this vulnerability to Siemens.

5. MITIGATIONS

Siemens has released updates for several affected products and recommends users update to the new version. Siemens is preparing further updates and recommends specific countermeasures until patches are available:

  • SIMATIC PCS 7 v8.2:  Install v8.2 SP1 (Includes SIMATIC WinCC v7.4 SP1 Upd6).

To obtain SIMATIC PCS 7 v8.2 SP1 contact your local support.

  • SIMATIC PCS 7 v9.0: Install v9.0 SP1:

To obtain SIMATIC PCS 7 v9.0 SP1 contact your local support.

  • SIMATIC BATCH v8.0: Install SIMATIC Batch v8.0 SP1 Upd21:

https://support.industry.siemens.com/cs/ww/en/view/109756847 

  • SIMATIC BATCH v8.1: Install SIMATIC Batch v8.1 SP1 Upd16:

https://support.industry.siemens.com/cs/ww/en/view/109756846

  • SIMATIC WinCC Runtime Professional: Update to v14 SP1 Upd5:

https://support.industry.siemens.com/cs/ww/en/view/109747394

  • SIMATIC WinCC v7.3: Update to WinCC 7.3 Upd16:

https://support.industry.siemens.com/cs/ww/en/view/109756123 

  • SIMATIC WinCC v7.4: Update to v7.4 SP1 Upd4:

https://support.industry.siemens.com/cs/ww/en/view/109753031 

——— Begin Update D Part 2 of 2 ——–
  • SIMATIC BATCH v8.2: Update to SIMATIC BATCH v8.2 Upd10:

https://support.industry.siemens.com/cs/ww/en/view/109757796

  • SIMATIC PCS 7 v8.2: Update to v8.2 SP1

To obtain SIMATIC PCS 7 v8.2 SP1 contact your local support.

  • SIMATIC Route Control v8.2:

To obtain SIMATIC PCS 7 v8.2 SP1 contact local support.

——— End Update D Part 2 of 2 ———-

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

  • Upgrade to a newer PCS 7 version.
  • Ensure that SIMATIC WinCC, SIMATIC WinCC Runtime Professional and SIMATIC PCS 7 stations communicate via encrypted channels (i.e., activate feature “Encrypted Communication” in SIMATIC WinCC v7.3 or newer and SIMATIC PCS 7 v8.1 or newer). Enabling “Encrypted Communication” completely mitigates the vulnerability.
  • Apply cell protection concept.
  • Use VPN for protecting network communication between cells.
  • Apply Defense-in-Depth.

As a general security measure, Siemens strongly recommends protecting network access to devices with appropriate mechanisms. In order to run the devices in a protected IT environment, Siemens particularly recommends that users configure the environment according to Siemens’ Operational Guidelines for Industrial Security and 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 on this vulnerability and associated software updates, please see Siemens security advisory SSA-348629 on their website:

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

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 in the ICS-CERT Technical Information Paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies, that is available for download from the ICS-CERT website.

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. This vulnerability is exploitable remotely. Low skill level is needed to exploit.

 

Source:

https://ics-cert.us-cert.gov/advisories/ICSA-18-088-03