CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:N/I:P/A:N
EPSS
Percentile
59.9%
This advisory provides mitigation details provided by Siemens for a vulnerability that impacts the Siemens S7-1200 Web Application Module.
Siemens has reportedSSA-279823, http://www.siemens.com/corporate-technology/en/research-areas/siemens-cert-security-advisories.htm, Web site last accessed October 9, 2012. a cross-site scripting (XSS) vulnerability in Siemensโs S7-1200 Programmable Logic Controllers (PLCs). Positive TechnologiesPositive Technologies, http://ptsecurity.com/, Web site last accessed October 9, 2012. discovered this vulnerability and reported it directly to Siemens. Siemens has provided mitigations and a firmware update to fix this vulnerability.
Exploitation of this vulnerability would allow an attacker to partially modify application data and limit the availability of the device. This vulnerability affects the electric, critical manufacturing, chemical, and food and beverage sectors.
This vulnerability can be exploited remotely.
Siemens reports that the vulnerabilities affect the following versions of S7-1200 PLCs:
An attacker that successfully exploits this vulnerability can run malicious JavaScript code on the target machine. Malicious code can execute various actions such as modify browser contents delivered from the PLC, steal session data, and issue commands from the PLCโs Web server.
Impact to individual organizations depends on many factors that are unique to each organization. ICS-CERT recommends that organizations evaluate the impact of these vulnerabilities based on their operational environment, architecture, and product implementation.
Products in the Siemens SIMATIC S7-1200 PLC family have been designed for process control in industrial environments such as manufacturing, power generation and distribution, food and beverages, and chemical industries worldwide.
The Web application does not filter user input in a way that prevents cross-site scripting. If a user is enticed into passing specially crafted, malicious input to the S7-1200 Web application via an HTTP request (e.g., by clicking on a malicious URL with embedded JavaScript), JavaScript code can be returned and may then be executed by the userโs browser. Various actions could be triggered by running malicious JavaScript code, including modification of browser content delivered from the PLC; stealing data, such as session cookies; issuing commands in the guise of the user to the PLCโs Web server.
CVE-2012-3040NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2012-3040 , 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 8.3 has been assigned; the CVSS vector string is (AV:N/AC:M/Au:N/C:P/I:P/A:C).CVSS Calculator, http://nvd.nist.gov/cvss.cfm?version=2&vector=AV:N/AC:M/Au:N/C:P/I:P/A:C, Web site last accessed October 9, 2012.
This vulnerability could be exploited remotely.
No known public exploits specifically target this vulnerability.
An attacker with medium skill level would be able to exploit this vulnerability.
Siemens has released a security advisorySiemens Security Advisory, http://www.siemens.com/corporate- technology/pool/de/forschungsfelder/siemens_security_advisory_ssa-279823.pdf, Website last accessed October 9, 2012. that details this vulnerability. It recommends users obtain the new updated firmware for Versions 3.0.0 and 3.0.1 of the S7-1200 by contacting Technical Support in their region:
Siemens also advises users who are unable to apply this firmware update to use the following mitigations.
For this version of firmware (3.0.2), Siemens has also removed the HTTP PUT functionality, because it is not used by the S7-1200 Web server.
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 US-CERT Web page. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth StrategiesCSSP Recommended Practices, http://www.us-cert.gov/control_systems/practices/Recommended_Practices.html, Web site last accessed October 9, 2012.. ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to taking defensive measures.
Additional mitigation guidance and recommended practices are publicly available in the ICS-CERT Technical Information Paper, ICS-TIP-12-146-01AโCyber Intrusion Mitigation Strategies.
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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