Siemens SIMATIC eaSie Core Package

1. EXECUTIVE SUMMARY

• CVSS v3 10.0
• ATTENTION: Exploitable remotely/low attack complexity
• Vendor: Siemens
• Equipment: SIMATIC eaSie
• Vulnerabilities: Improper Input Validation, Missing Authentication for Critical Function

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an unauthenticated attacker to send arbitrary messages within the affected system or to crash attached applications.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of SIMATIC eaSie, a digital automation manager, are affected:

• Core Package (6DL5424-0AX00-0AV8): All versions prior to v22.00

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER INPUT VALIDATION CWE-20

The affected systems do not properly validate inputs that are sent to the underlying message passing framework. This could allow a remote attacker to trigger a denial of service of the affected system.

CVE-2021-44221 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

3.2.2    MISSING AUTHENTICATION FOR CRITICAL FUNCTION CWE-306

The underlying MQTT service of affected systems does not perform authentication in the default configuration. This could allow an unauthenticated remote attacker to send arbitrary messages to the service and thereby issue arbitrary requests in the affected system.

CVE-2021-44222 has been assigned to this vulnerability. A CVSS v3 base score of 10.0 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N).

3.3 BACKGROUND

• CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
• COUNTRIES/AREAS DEPLOYED: Worldwide
• COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

Siemens reported these vulnerabilities to CISA.

4. MITIGATIONS

Siemens recommends users update affected products to v22.00 or later.

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

Additional information on industrial security by Siemens can be found on the Siemens industrial security webpage.

For more information see Siemens Security Advisory SSA-580125

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 these vulnerabilities.

• Siemens