Siemens SIMATIC Authentication Bypass (Update D)

1. EXECUTIVE SUMMARY

• CVSS v3 9.0

• ATTENTION: Remotely exploitable/low skill level to exploit

• Vendor: Siemens

• Equipment: SIMATIC

• Vulnerability: Improper Authentication

2. UPDATE INFORMATION

This updated advisory is a follow-up to the updated advisory titled ICSA-17-045-03C Siemens SIMATIC Authentication Bypass that was published November 30, 2017, on the NCCIC/ICS-CERT website.

3. RISK EVALUATION

Successful exploitation of this vulnerability could allow attackers to circumvent user authentication under certain conditions.

4. TECHNICAL DETAILS

4.1 AFFECTED PRODUCTS

--------- Begin Update D Part 1 of 1 --------

Siemens reports this vulnerability affects the following software applications used for central user administration:

• SIMATIC Logon: All versions prior to v1.5 SP3 Update 2

The following products include affected versions of SIMATIC Logon:

• SIMATIC WinCC: All versions prior to v7.4 SP1,
• SIMATIC WinCC Runtime Professional: All versions prior to v14 SP1,
• SIMATIC PCS 7: All versions prior to v8.2 SP1,
• SIMATIC PDM: All versions prior to v9.1, and
• SIMATIC IT: All versions prior to v7.1

--------- End Update D Part 1 of 1 ----------

4.2 VULNERABILITY OVERVIEW

4.2.1 IMPROPER AUTHENTICATION CWE-287

An attacker with knowledge of a valid user name, and physical or network access to the affected system could bypass the application-level authentication.

CVE-2017-2684 has been assigned to this vulnerability. A CVSS v3 base score of 9.0 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H).

4.3 BACKGROUND

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

4.4 RESEARCHER

Siemens reported this vulnerability to ICS-CERT.

5. MITIGATIONS

Siemens provides SIMATIC Logon v1.5 SP3 Update 2 and recommends that users update to the new version. Users using recent versions of SIMATIC WinCC, SIMATIC PCS 7, SIMATIC IT, SIMATIC IT Production Suite, or SIMATIC PDM can install the new version of SIMATIC Logon without an update of these products as described in the compatibility note that can be accessed via the download link below:

<https://support.industry.siemens.com/cs/ww/en/view/109744966&gt;

For more information on this vulnerability and more detailed mitigation instructions, see Siemens Security Advisory SSA-931064 at the following location:

<http://www.siemens.com/cert/en/cert-security-advisories.htm&gt;

As a general security measure Siemens strongly recommends configuring the environment according to Siemens’ operational guidelines in order to run the devices in a protected IT environment.

<https://www.siemens.com/cert/operational-guidelines-industrial-security&gt;

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. High skill level is needed to exploit.