. EXECUTIVE SUMMARY
CVSS v3 10.0
- ATTENTION: Exploitable remotely/low skill level to exploit
- Vendor: Siemens
- Equipment: WibuKey Digital Rights Management (DRM) used with SICAM 230
- Vulnerabilities: Improper Input Validation
2. RISK EVALUATION
Successful exploitation of these vulnerabilities may allow information disclosure, privilege escalation, or remote code execution.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following versions of Siemens SICAM 230, a process control system, are affected by vulnerabilities in WibuKey Digital Rights Management (DRM):
- SICAM 230: All Versions 7.20 and prior
3.2 VULNERABILITY OVERVIEW
A specially crafted IRP (I/O request packet) can cause the driver to return uninitialized memory, which may result in kernel memory disclosure.
A specially crafted IRP (I/O request packet) can cause a buffer overflow, resulting in kernel memory corruption, which may allow privilege escalation.
A specially crafted TCP packet sent to Port 22347/TCP can cause a heap overflow, which may lead to remote code execution.
- CRITICAL INFRASTRUCTURE SECTORS: Energy
- COUNTRIES/AREAS DEPLOYED: Worldwide
- COMPANY HEADQUARTERS LOCATION: Germany
Siemens reported these vulnerabilities to NCCIC.
Siemens recommends users upgrade to WibuKey Digital Rights Management (DRM) Version 6.50 or higher from WIBU SYSTEMS AG, which can be found at:
Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:
- CVE-2018-3991 can be mitigated by blocking Port 22347/TCP e.g., on an external firewall.
Siemens strongly recommends applying the provided security updates using the corresponding tooling and documented procedures made available with the product. If supported by the product, an automated means to apply the security updates across multiple product instances may be used. Siemens strongly recommends prior validation of any security update before being applied, and supervision by trained staff of the update process in the target environment.
As a general security measure Siemens strongly recommends protecting network access with appropriate mechanisms (e.g., firewalls, segmentation, VPN). Users are advised to configure the environment according to Siemens operational guidelines in order to run the devices in a protected IT environment. Recommended security guidelines to secure substations can be found at: https://www.siemens.com/gridsecurity.
For additional information see Siemens’ security advisory SSA-760124 at the following location:
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 these vulnerabilities.