As of January 10, 2023, CISA will no longer be updating ICS security advisories for Siemens product vulnerabilities beyond the initial advisory. For the most up-to-date information on vulnerabilities in this advisory, please see Siemens’ ProductCERT Security Advisories (CERT Services | Services | Siemens Global).
1. EXECUTIVE SUMMARY
- CVSS v3 9.8
- ATTENTION: Exploitable remotely/low attack complexity
- Vendor: Siemens
- Equipment: SIPROTEC 4 7SJ66
- Vulnerabilities: Classic Buffer Overflow, Session Fixation, NULL Pointer Dereference, Origin Validation Error, Race Condition, Missing Release of Memory after Effective Lifetime
2. RISK EVALUATION
Successful exploitation of these vulnerabilities could allow an attacker to execute a variety of exploits for the purpose of denial-of-service, data extraction, remote code execution, etc.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
Siemens reports that the following SIPROTEC products are affected due to vulnerabilities in the underlying Wind River VxWorks network stack:
- SIPROTEC 4 7SJ66: versions prior to V4.41
3.2 Vulnerability Overview
Wind River VxWorks has a buffer overflow in the TCP component (issue 1 of 4). This is a IPNET security vulnerability: TCP Urgent Pointer = 0 that leads to an integer underflow.
Wind River VxWorks 6.9 and vx7 has a buffer overflow in the IPv4 component. There is an IPNET security vulnerability: Stack overflow in the parsing of IPv4 packets’ IP options.
3.2.3 SESSION FIXATION CWE-384
Wind River VxWorks 6.6 through vx7 has session fixation in the TCP component. This is a IPNET security vulnerability: DoS of TCP connection via malformed TCP options.
Wind River VxWorks 6.6, 6.7, 6.8, 6.9 and vx7 has an array index error in the IGMPv3 client component. There is an IPNET security vulnerability: DoS via NULL dereference in IGMP parsing.
Wind River VxWorks 6.9 and vx7 has a buffer overflow in the TCP component (issue 2 of 4). This is an IPNET security vulnerability: TCP Urgent Pointer state confusion caused by a malformed TCP AO option.
Wind River VxWorks 6.7 though 6.9 and vx7 has a buffer overflow in the TCP component (issue 3 of 4). This is an IPNET security vulnerability: TCP Urgent Pointer state confusion during connect () to a remote host.
Wind River VxWorks 6.6, 6.7, 6.8, 6.9 and 7 has incorrect access control in the RARP client component. IPNET security vulnerability: Handling of unsolicited Reverse ARP replies (Logical Flaw).
Wind River VxWorks 6.9.4 and vx7 has a buffer overflow in the TCP component (issue 4 of 4). There is an IPNET security vulnerability: TCP Urgent Pointer state confusion due to race condition.
Wind River VxWorks 6.5, 6.6, 6.7, 6.8, 6.9.3 and 6.9.4 has a memory leak in the IGMPv3 client component. There is an IPNET security vulnerability: IGMP Information leak via IGMPv3 specific membership report.
- CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing
- COUNTRIES/AREAS DEPLOYED: Worldwide
- COMPANY HEADQUARTERS LOCATION: Germany
Siemens ProductCERT reported these vulnerabilities to CISA.
Siemens has released a new version (V4.41 or later version) for SIPROTEC 4 7SJ66 and recommends users update to the latest version.
As a general security measure, Siemens recommends protecting network access to devices with appropriate mechanisms. To operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens’ operational guidelines for industrial security and following recommendations in the product manuals.
Additional information on industrial security by Siemens can be found on the Siemens industrial security webpage.
CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities, such as:
- Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
- Locate control system networks and remote devices behind firewalls and isolating them from business networks.
- When remote access is required, use more secure methods, such as virtual private networks (VPNs). Recognize VPNs may have vulnerabilities, should be updated to the most recent version available, and are only as secure as the 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. 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.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov 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 exploitation specifically targeting these vulnerabilities has been reported to CISA at this time.
5. UPDATE HISTORY
- November 16, 2023: Initial Publication