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AUSCERT External Security Bulletin Redistribution
ESB-2015.0160
Siemens SIMATIC S7-1200 CPU Web Vulnerability
23 January 2015
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AusCERT Security Bulletin Summary
---------------------------------
Product: Siemens SIMATIC S7-1200 CPU Family
Publisher: ICS-CERT
Operating System: Network Appliance
Impact/Access: Provide Misleading Information -- Remote with User Interaction
Resolution: Patch/Upgrade
CVE Names: CVE-2015-1048
Original Bulletin:
https://ics-cert.us-cert.gov/advisories/ICSA-15-022-01
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Advisory (ICSA-15-022-01)
Siemens SIMATIC S7-1200 CPU Web Vulnerability
Original release date: January 22, 2015
Legal Notice
All information products included in http://ics-cert.us-cert.gov are provided
"as is" for informational purposes only. The Department of Homeland Security
(DHS) does not provide any warranties of any kind regarding any information
contained within. DHS does not endorse any commercial product or service,
referenced in this product or otherwise. Further dissemination of this product
is governed by the Traffic Light Protocol (TLP) marking in the header. For
more information about TLP, see http://www.us-cert.gov/tlp/.
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 Brggemann 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 REDIRECT[a]
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-2015-1048[b] 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.
a. CWE-601: URL Redirection to Untrusted Site ('Open Redirect'),
http://cwe.mitre.org/data/definitions/601.html, web site last accessed January
22, 2015.
b. NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-1048, NIST
uses this advisory to create the CVE web site report. This web site will be
active sometime after publication of this advisory.
c. CVSS Calculator,
http://nvd.nist.gov/cvss.cfm?version=2&vector=AV:N/AC:M/Au:N/C:N/I:P/A:N, web
site last accessed January 22, 2015.
Contact Information
For any questions related to this report, please contact ICS-CERT at:
Email: ics-cert@hq.dhs.gov
Toll Free: 1-877-776-7585
International Callers: (208) 526-0900
For industrial control systems security information and incident reporting:
http://ics-cert.us-cert.gov
ICS-CERT continuously strives to improve its products and services. You can
help by choosing one of the links below to provide feedback about this
product.
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Australian Computer Emergency Response Team
The University of Queensland
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Internet Email: auscert@auscert.org.au
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