Siemens SIMATIC S7-1200 CPU Family Version 4

1. EXECUTIVE SUMMARY

• CVSS v3 7.5
• ATTENTION: Exploitable remotely
• Vendor: Siemens
• Equipment: SIMATIC S7-1200 CPU Family Version 4
• Vulnerability: Cross-Site Request Forgery (CSRF)

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow a CSRF attack if an unsuspecting user is tricked into accessing a malicious link.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

Siemens reports the vulnerability affects the following SIMATIC S7-1200 CPU products:

• SIMATIC S7-1200 CPU Family Version 4: All versions prior to 4.2.3

3.2 VULNERABILITY OVERVIEW

3.2.1    CROSS-SITE REQUEST FORGERY (CSRF) CWE-352

The web interface could allow a CSRF attack if an unsuspecting user is tricked into accessing a malicious link. Successful exploitation requires interaction with a legitimate user, who must be authenticated to the web interface. A successful attack could allow an attacker to trigger actions via the web interface that the legitimate user is allowed to perform. This could allow the attacker to read or modify parts of the device configuration.

CVE-2018-13800 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:H/PR:N/UI:R/S:U/C:H/I:H/A:H).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Chemical, Energy, Food and Agriculture, Healthcare and Public Health, Transportation Systems, and Water and Wastewater Systems
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Lisa Fournet and Marl Joos from P3 communications GmbH reported this vulnerability to Siemens.

4. MITIGATIONS

Siemens provides a firmware update (v4.2.3) and recommends users update to the new version. This update can be found on their website at the following location:

https://support.industry.siemens.com/cs/us/en/view/109741461

To reduce the risk, Siemens recommends users not visit other websites while being authenticated against the PLC.

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 (https://www.siemens.com/cert/operational-guidelines-industrial-security), and following 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-507847 on their website:

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.

NCCIC also recommends that users take the following measures to protect themselves from social engineering attacks:

• Do not click web links or open unsolicited attachments in email messages.
• Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.
• Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks.

High skill level is needed to exploit.

• Siemens