CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:L/Au:N/C:N/I:N/A:C
EPSS
Percentile
96.8%
Johannes Klick, Christian Pfahl, Martin Gebert, and Lucas Jacob from Freie Universität Berlin’s work team SCADACS have identified a Denial-of-Service (DoS) vulnerability in Siemens SIMATIC S7-300 CPUs. Siemens has developed mitigations for this vulnerability.
This vulnerability could be exploited remotely.
The following SIMATIC S7-300 CPUs are affected:
This vulnerability could allow attackers to perform a DoS attack over the network without prior authentication against S7-300 CPUs under certain conditions. A cold restart is required to recover the system.
Impact to individual organizations depends on many factors that are unique to each organization. NCCIC/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 product, SIMATIC S7-300 CPU, have been designed for process control in industrial environments. This product is 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.
Specially crafted packets sent to Port 102/TCP (ISO-TSAP) or via Profibus could cause the affected device to go into defect mode. A cold restart is required to recover the system.
CVE-2015-2177NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-2177, NIST uses this advisory to create the CVE web site report. This web site will be active sometime after publication of this advisory. has been assigned to this vulnerability. A CVSS v2 base score of 7.8 has been assigned; the CVSS vector string is (AV:N/AC:L/Au:N/C:N/I:N/A:C).CVSS Calculator, http://nvd.nist.gov/cvss.cfm?version=2&vector=AV:N/AC:L/Au:N/C:N/I:N/A:C, web site last accessed March 05, 2015.
This vulnerability could be exploited remotely.
No known public exploits specifically target this vulnerability.
Crafting a working exploit for this vulnerability would be difficult.
Siemens recommends the following mitigations:
For more information on these vulnerabilities and detailed instructions, please see Siemens Security Advisory SSA-987029 at the following location:
http://www.siemens.com/cert/advisories
ICS-CERT encourages asset owners to take additional defensive measures to protect against this and other cybersecurity risks.
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:
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