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1. EXECUTIVE SUMMARY
- CVSS v3 9.8
- ATTENTION: Exploitable remotely
- Vendor: Siemens
- Equipment: SIMATIC HMIs/WinCC Products
- Vulnerabilities: Access of Memory Location After End of Buffer, Improper Handling of Exceptional Conditions, Improper Restriction of Operations within the Bounds of a Memory Buffer, Uncontrolled Resource Consumption
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow remote code execution, information disclosure and denial of service attacks under certain conditions.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
The following Siemens SIMATIC HMIs/WinCC products are affected:
- SIMATIC HMI Comfort Outdoor Panels 7’ and 15’ (incl. SIPLUS variants): All versions prior to v16 Update 4
- SIMATIC HMI Comfort Panels 4’-22’ (incl. SIPLUS variants): All versions prior to v16 Update 4
- SIMATIC HMI KTP Mobile Panels KTP400F, KTP700, KTP700F, KTP900, KTP900F: All versions prior to v16 Update 4
- SIMATIC WinCC Runtime Advanced: All versions prior to v16 Update 4
3.2 VULNERABILITY OVERVIEW
SmartVNC has an out-of-bounds memory access vulnerability that could be triggered on the server side when sending data from the client, which could result in a denial-of-service condition.
SmartVNC has an out-of-bounds memory access vulnerability that could be triggered on the client side when sending data from the server, which could result in a denial-of-service condition.
SmartVNC client fails to handle an exception properly if the program execution process is modified after sending a packet from the server, which could result in a denial-of-service condition.
SmartVNC has a heap allocation leak vulnerability in the server Tight encoder, which could result in a denial-of-service condition.
SmartVNC has an out-of-bounds memory access vulnerability in the device layout handler represented by a binary data stream on client side, which could result in code execution.
A remote attacker could send specially crafted packets to a SmartVNC device layout handler on the client side, which could influence the number of resources consumed and result in a denial-of-service condition (infinite loop).
SmartVNC has a heap allocation leak vulnerability in the device layout handler on client side, which could result in a denial-of-service condition.
- CRITICAL INFRASTRUCTURE SECTORS: Multiple Sectors
- COUNTRIES/AREAS DEPLOYED: Worldwide
- COMPANY HEADQUARTERS LOCATION: Germany
Siemens reported these vulnerabilities to CISA.
Siemens recommends applying updates where available:
- SIMATIC HMI Comfort Outdoor Panels 7’ and 15’ (incl. SIPLUS variants): Update to v16 Update 4 or later versions
- SIMATIC HMI Comfort Panels 4’-22’ (incl. SIPLUS variants): Update to v16 Update 4 or later versions
- SIMATIC HMI KTP Mobile Panels KTP400F, KTP700, KTP700F, KTP900, KTP900F: Update to v16 Update 4 or later versions
- SIMATIC WinCC Runtime Advanced: Update to v16 Update 4 or later versions
Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:
- Restrict access to Port 5900/TCP to trusted IP addresses only
As a general security measure, Siemens strongly recommends protecting network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends configuring the environment according to the Siemens operational guidelines for industrial security and following the recommendations in the product manuals.
For additional information, please refer to Siemens Security Advisory SSA-538778
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 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 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 us-cert.cisa.gov. 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 webpage on us-cert.cisa.gov 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 CISA for tracking and correlation against other incidents.
For any questions related to this report, please contact the CISA at:
Toll Free: 1-888-282-0870
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