Siemens WinCC OA

1. EXECUTIVE SUMMARY

• CVSS v3 9.8
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Siemens
• Equipment: SIMATIC WinCC OA
• Vulnerability: Use of Client-side Authentication

CISA is aware of a public report, known as “OT:ICEFALL” that details vulnerabilities found in multiple operational technology (OT) vendors. CISA is issuing this advisory to provide notice of the reported vulnerabilities and identify baseline mitigations for reducing risks to these and other cybersecurity attacks.

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to impersonate other users or exploit the client-server protocol without being authenticated.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of SIMATIC WinCC OA, a SCADA HMI system, are affected:

• SIMATIC WinCC OA v3.16: All versions
• SIMATIC WinCC OA v3.17: All versions
• SIMATIC WinCC OA v3.18: All versions

3.2 VULNERABILITY OVERVIEW

3.2.1    USE OF CLIENT-SIDE AUTHENTICATION CWE-603

Affected applications use client-side only authentication when neither server-side authentication nor Kerberos authentication is enabled. In this configuration, attackers could impersonate other users or exploit the client-server protocol without being authenticated.

CVE-2022-33139 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.3 BACKGROUND

•    CRITICAL INFRASTRUCTURE SECTORS: Multiple Sectors

•    COUNTRIES/AREAS DEPLOYED: Worldwide

•    COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Daniel dos Santos and Jos Wetzels from Forecout Technologies reported this vulnerability to CISA.

4. MITIGATIONS

Siemens recommends the following mitigations or workarounds:

• Enable server-side authentication (SSA) or Kerberos authentication for your WinCC OA project (login required).
  • SIMATIC WinCC OA v3.16 SSA
  • SIMATIC WinCC OA v3.17 SSA
  • SIMATIC WinCC OA v3.18 SSA

As a general security measure, Siemens recommends protecting network access to devices with appropriate mechanisms. To operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens’ operational guidelines for industrial security and following recommendations in the product manuals.

For additional information, please refer to Siemens Security Advisory SSA-111512

Remarks by ETM regarding SSA-11512 for SIMATIC WinCC OA

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 cisa.gov/ics 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 cisa.gov/ics 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.

• Siemens