Fr. Sauter AG CASE Suite

1. EXECUTIVE SUMMARY

• CVSS v3 7.5
• ATTENTION: Exploitable remotely/low skill level to exploit
• Vendor: Fr. Sauter AG
• Equipment: CASE Suite
• Vulnerability: Improper Restriction of XML External Entity Reference

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to remotely retrieve unauthorized files from the system.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of CASE Suite are affected:

• CASE Suite Versions 3.10 and prior.

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER RESTRICTION OF XML EXTERNAL ENTITY REFERENCE ('XXE') CWE-611

An XXE vulnerability exists when processing parameter entities, which may allow remote file disclosure.

CVE-2018-17912 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:H/I:N/A:N).

3.3 BACKGROUND

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

3.4 RESEARCHER

Gjoko Krstic of Applied Risk reported this vulnerability to NCCIC.

4. MITIGATIONS

Fr. Sauter AG recommends users apply Service Release 1 for the current CASE Suite Version 3.10. The software is deployed via local support channels.

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.

• Fr. Sauter AG