Siemens Desigo CC and Cerberus DMS

1. EXECUTIVE SUMMARY

• CVSS v3 9.8 *ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Siemens
• Equipment: Desigo CC and Cerberus DMS
• Vulnerability: Use of Client-Side Authentication

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 Siemens management stations are affected:

• Desigo CC: All versions
• Desigo CC Compact: All versions
• Cerberus DMS: All versions

3.2 VULNERABILITY OVERVIEW

3.2.1 USE OF CLIENT-SIDE AUTHENTICATION CWE-603

All versions of Siemens Desigo CC and Cerberus DMS use client-side 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
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Siemens reported this vulnerability to CISA.

4. MITIGATIONS

Siemens recommends users implement workarounds and mitigations for the affected products to reduce risk.

As a general security measure, Siemens strongly recommends protecting network access to affected products with appropriate mechanisms. It is advised to follow recommended security practices to run the devices in a protected IT environment.

For more information see, Siemens security advisory SSA-836027 in HTML or CSAF.

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability these vulnerabilities. Specifically, users should:

• Minimize network exposure for all control system devices and/or systems, and ensure they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls and isolate them from business networks.
• When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as its connected devices.

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 at cisa.gov/ics. Several CISA products detailing cyber defense best 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 at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.

No known public exploits specifically target this vulnerability.