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TLP:WHITE

Advisory (ICSA-15-022-01)

Siemens SIMATIC S7-1200 CPU Web Vulnerability

Original release date: January 22, 2015

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OVERVIEW

Siemens has identified an open redirect vulnerability in the SIMATIC S7-1200 CPU family. This vulnerability was reported directly to Siemens by Ralf Spenneberg, Hendrik Schwartke, and Maik Brüggemann from OpenSource Training. Siemens has produced an update that mitigates this vulnerability.

This vulnerability could be exploited remotely.

AFFECTED PRODUCTS

The following Siemens SIMATIC S7-1200 CPU family versions are affected:

  • SIMATIC S7-1200 CPU family: All versions prior to V4.1

IMPACT

This vulnerability could allow an attacker to redirect users to untrusted sites under certain conditions.

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.

BACKGROUND

Siemens is a multinational company headquartered in Munich, Germany.

Products in the Siemens SIMATIC S7-1200 CPU family have been designed for discrete and continuous control in critical infrastructure sectors such as Chemical, Critical Manufacturing, and Food and Agriculture.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

OPEN REDIRECTa

The integrated web server (Port 80/TCP and Port 443/TCP) of the affected devices could allow an attacker to redirect users to untrusted web sites if unsuspecting users are tricked to click on a malicious link.

CVE-2015-1048b has been assigned to this vulnerability. A CVSS v2 base score of 4.3 has been assigned; the CVSS vector string is (AV:N/AC:M/Au:N/C:N/I:P/A:N).c

VULNERABILITY DETAILS

EXPLOITABILITY

This vulnerability could be exploited remotely.

EXISTENCE OF EXPLOIT

No known public exploits specifically target this vulnerability.

DIFFICULTY

An attacker with a medium skill would be able to exploit this vulnerability.

MITIGATION

Siemens provides the SIMATIC S7-1200 CPU firmware release V4.1, which fixes the vulnerability.

http://support.automation.siemens.com/WW/view/en/106200276

For more information on these vulnerabilities and detailed instructions, please see Siemens Security Advisory SSA-597212 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.

  • 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 that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the connected devices.

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.


Contact Information

For any questions related to this report, please contact the NCCIC at:

Email: NCCICCUSTOMERSERVICE@hq.dhs.gov
Toll Free: 1-888-282-0870

For industrial control systems cybersecurity information:  http://ics-cert.us-cert.gov 
or incident reporting:  https://ics-cert.us-cert.gov/Report-Incident?

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