Siemens SIMOTICS, Desigo, APOGEE, and TALON (Update D)

1. EXECUTIVE SUMMARY

• CVSS v3 7.1
• ATTENTION: Exploitable from an adjacent network/low skill level to exploit
• Vendor: Siemens
• Equipment: SIMOTICS, Desigo, APOGEE, and TALON
• Vulnerability: Business Logic Errors

2. UPDATE INFORMATION

This updated advisory is a follow-up to the advisory update titled ICSA-20-105-06 Siemens SIMOTICS, Desigo, APOGEE, and TALON (Update C) that was published April 14, 2021, on the ICS webpage at cisa.gov/ics.

3. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to affect the availability and integrity of the device.

4. TECHNICAL DETAILS

4.1 AFFECTED PRODUCTS

Siemens reports the vulnerability affects the following products and versions:

• APOGEE MEC/MBC/PXC (P2): All versions prior to 2.8.2

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• APOGEE PXC Series (P2): All versions between 2.8.2 and v2.8.19

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• Desigo PXC00-E.D: All versions, 2.3x to v6.00.327
• Desigo PXC00-U: All versions, 2.3x to v6.00.327
• Desigo PXC001-E.D: All versions, 2.3x to v6.00.327
• Desigo PXC12-E.D: All versions, 2.3x to v6.00.327
• Desigo PXC22-E.D: All versions, 2.3x to v6.00.327
• Desigo PXC22.1-E.D: All versions, 2.3x to v6.00.327
• Desigo PXC36.1-E.D: All versions, 2.3x to v6.00.327
• Desigo PXC50-E.D: All versions, 2.3x to v6.00.327
• Desigo PXC64-U: All versions, 2.3x to v6.00.327
• Desigo PXC100-E.D: All versions, 2.3x to v6.00.327
• Desigo PXC128-U: All versions, 2.3x to v6.00.327
• Desigo PXC200-E.D: All versions, 2.3x to v6.00.327
• Desigo PXM20-E: All versions, 2.3x to v6.00.327
• SIMOTICS CONNECT 400: All versions prior to 0.3.0.330
• TALON TC Series (BACnet): All versions prior to 3.5.3
• APOGEE PXC Series (BACnet): All versions prior to 3.5.3

4.2 VULNERABILITY OVERVIEW

4.2.1    BUSINESS LOGIC ERRORS CWE-840

The affected products could allow an attacker to change the IP address of the device to an invalid value. This may allow an attacker to make device configuration changes and affect its availability.

CVE-2019-13939 has been assigned to this vulnerability. A CVSS v3 base score of 7.1 has been assigned; the CVSS vector string is (AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H).

4.3 BACKGROUND

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

4.4 RESEARCHER

Siemens reported this vulnerability to CISA.

5. MITIGATIONS

Siemens recommends users update to the latest version of their software where applicable.

• Desigo Products: Update to v6.00.327
• SIMOTICS CONNECT 400: Update to v0.3.0.330
• TALON TC Series (BACnet): Update to v3.5.3
• APOGEE PXC Series (BACnet): Update to v3.5.3

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• APOGEE PXC Series (P2): Update to v2.8.19 or later (contact Siemens for assistance)

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

• Disable the DHCP client and use static IP address configuration instead (Note that the DHCP client is disabled by default on APOGEE/TALON and Desigo products).
• APOGEE MEC, MBC, PXC (versions prior to v2.8.2): Use static IP address configuration as described above
• APOGEE PXC Series and TALON TC Series products: If using a static IP address is not possible, update to the fix version listed above or contact your local Siemens office for support.

As a general security measure Siemens strongly recommends users protect network access to affected products with appropriate mechanisms. Users are advised to follow recommended security practices in order to run the devices in a protected IT environment. Additional information on industrial security by Siemens can be found at: https://www.siemens.com/industrialsecurity

For more information see Siemens Security Advisory SSA-162506

CISA 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 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 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 on cisa.gov/ics. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth 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