This updated advisory is a follow-up to the original advisory titled ICSA-15-064-01 Siemens SIMATIC HMI Basic, SINUMERIK, and Ruggedcom APE GHOST Vulnerability that was published March 5, 2015, on the NCCIC/ICS-CERT web site.
The “GHOST”a vulnerability in the glibc library affects the Siemens SINUMERIK and SIMATIC HMI Basic applications. Siemens has produced an update for SINUMERIK that mitigates this vulnerability.
Siemens has released an update for SIMATIC HMI Basic Panels.
The following SINUMERIK and SIMATIC HMI Basic versions are affected:
The following Ruggedcom APE versions are not vulnerable in their default configuration, but can become exploitable depending on components installed and user configuration:
Ruggedcom APE: APE1402-XX, APE1402-C01, APE1404-XX, APE1404-C01, all versions.
An authenticated local user could cause a denial of service of the targeted system by exploiting this vulnerability.
Impact to individual organizations depends on many factors that are unique to each organization. ICS-CERT recommends that organizations evaluate the impact of this vulnerability based on their operational environment, architecture, and product implementation.
Siemens is a multinational company headquartered in Munich, Germany.
The affected products, SINUMERIK, SIMATIC HMI Basic, and Ruggedcom, are used as an interface between operators and corresponding systems, as well as the ability to run third-party components. These products are deployed across several sectors including: Chemical, Energy, Food and Agriculture, and Water and Wastewater Systems. Siemens estimates that these products are used primarily in the United States and Europe with a small percentage in Asia.
Incorrect parsing within the glibc library functions “gethostbyname()” and “gethostbyname2()” could cause a denial of service of the targeted system.
CVE-2015-0235c has been assigned to this vulnerability. A CVSS v2 base score of 4.6 has been assigned; the CVSS vector string is (AV:L/AC:L/Au:S/C:N/I:N/A:C).d
In order to exploit the SINUMERIK and SIMATIC HMI Basic products, an attacker would first need to have authenticated local access to the device(s). To exploit the Ruggedcom APE product an attacker would need to be able to influence parameters passed to the vulnerable functions. This is only possible if the user has installed components that utilize the vulnerable functions and that are accessible to the attacker.
No known public exploits specifically target these products. However, public exploits for the “GHOST” vulnerability do exist.
An attacker with local access and a low skill would be able to exploit this vulnerability.
Siemens has released security advisory SSA-994726 at the following location: <http://www.siemens.com/cert/advisories>
Siemens has provided updates for the following products and encourages customers to upgrade the products to the newest version:
ICS-CERT encourages asset owners to take additional defensive measures to protect against this and other cybersecurity risks.
Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
ICS-CERT also provides a section for control systems security recommended practices on the ICS-CERT web page at: <http://ics-cert.us-cert.gov/content/recommended-practices>. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies. ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
Additional mitigation guidance and recommended practices are publicly available in the ICS‑CERT Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies, that is available for download from the ICS-CERT web site (<http://ics-cert.us-cert.gov/>).
Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to ICS-CERT for tracking and correlation against other incidents.
In addition, ICS-CERT recommends that users take the following measures to protect themselves from social engineering attacks: