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AUSCERT External Security Bulletin Redistribution
ESB-2017.2188.2
Advisory (ICSA-17-243-01) Siemens industrial products using the Discovery
Service of the OPC UA protocol stack by the OPC foundation
4 October 2017
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AusCERT Security Bulletin Summary
---------------------------------
Product: SIMATIC PCS 7
SIMATIC WinCC
SIMATIC NET PC Software
SIMATIC IT Production Suite
Publisher: ICS-CERT
Operating System: Windows
Network Appliance
Impact/Access: Denial of Service -- Remote/Unauthenticated
Access Confidential Data -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2017-12069
Original Bulletin:
https://ics-cert.us-cert.gov/advisories/ICSA-17-243-01
Revision History: October 4 2017: Updated Product and Mitigation
September 1 2017: Initial Release
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Advisory (ICSA-17-243-01A)
Siemens Industrial products using the Discovery Service of the OPC UA protocol
stack by the OPC foundation
Original release date: October 03, 2017
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/.
CVSS v3 8.2
ATTENTION: Remotely exploitable/low skill level to exploit.
Vendor: Siemens
Equipment: Industrial products using the Discovery Service of the OPC UA
protocol stack by the OPC foundation
Vulnerability: Improper Restriction of XML External Entity Reference
UPDATE INFORMATION
This updated advisory is a follow-up to the original advisory titled
ICSA-17-242-01 Siemens Industrial products using the Discovery Service of the
OPC UA protocol stack by the OPC foundation that was published August 31,
2017, on the NCCIC/ICS-CERT web site.
AFFECTED PRODUCTS
- --------- Begin Update A Part 1 of 2 --------
Siemens reports that the vulnerability affects the following industrial
products, which use the Discovery Service of the OPC UA protocol stack by the
OPC foundation:
SIMATIC PCS 7
V8.0: All versions
V8.1: All versions
SIMATIC WinCC:
V7.2: All versions
SIMATIC WinCC Runtime Professional:
V13: All versions
V14: All versions prior to V14 SP1
SIMATIC NET PC Software: All versions
SIMATIC IT Production Suite: All versions prior to V6.5
- --------- End Update A Part 1 of 2 --------
IMPACT
Successful exploitation of this vulnerability may allow an attacker to access
various resources.
MITIGATION
- --------- Begin Update A Part 2 of 2 --------
Siemens provides fixes for the following products and recommends users upgrade
to the newest version:
SIMATIC PCS 7:
All affected versions: Follow FAQ:
https://support.industry.siemens.com/cs/ww/en/view/109749461 (link is
external)
SIMATIC WinCC:
All versions: Follow FAQ to turn off the service after commissioning:
https://support.industry.siemens.com/cs/ww/en/view/109749461 (link is
external)
SIMATIC WinCC Runtime Professional:
Update to V14 SP1
https://support.industry.siemens.com/cs/ww/en/view/109746276 (link is
external)
All other versions: Follow FAQ to turn off the service after
commissioning:
https://support.industry.siemens.com/cs/ww/en/view/109749461 (link is
external)
SIMATIC NET PC Software:
Follow FAQ to turn off the service after commissioning:
https://support.industry.siemens.com/cs/ww/en/view/109749461 (link is
external)
- --------- End Update A Part 2 of 2 --------
Siemens is preparing further updates and recommends the following mitigations
in the meantime:
Turn off the Discovery Service or block it on the local firewall,
Apply cell protection concept,
Use VPN for protecting network communication between cells, and
Apply Defense in Depth.
Siemens recommends users protect network access with appropriate mechanisms
such as firewalls, segmentation, and VPNs. Siemens also advises that users
configure the operational environment according to Siemens Operational
Guidelines for Industrial Security:
https://www.siemens.com/cert/operational-guidelines-industrial-security (link
is external)
For more information on this vulnerability and more detailed mitigation
instructions, please see Siemens Security Advisory SSA-535640 at the following
location:
http://www.siemens.com/cert/advisories (link is external)
The OPC Foundation also published a security bulletin for this vulnerability:
https://opcfoundation-onlineapplications.org/faq/SecurityBulletins/OPC_Foundation_Security_Bulletin_CVE-2017-12069.pdf
ICS-CERT recommends that users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:
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 reminds organizations to perform proper impact analysis and risk
assessment prior to deploying defensive measures.
ICS-CERT also provides a section for control systems security recommended
practices on the ICS-CERT web page. Several recommended practices are
available for reading and download, including Improving Industrial Control
Systems Cybersecurity with Defense-in-Depth Strategies.
Additional mitigation guidance and recommended practices are publicly
available in the ICSCERT 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.
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.
No known public exploits specifically target this vulnerability.
VULNERABILITY OVERVIEW
IMPROPER RESTRICTION OF XML EXTERNAL ENTITY REFERENCE ('XXE') CWE-611
By sending specially crafted packets to the OPC Discovery Server at Port
4840/TCP, an attacker might cause the system to access various resources
chosen by the attacker.
CVE-2017-12069 has been assigned to this vulnerability. A CVSS v3 base score
of 8.2 has been assigned; the CVSS vector string is
(AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H).
RESEARCHER
Sergey Temnikov of Kaspersky Lab reported this vulnerability to Siemens.
BACKGROUND
Critical Infrastructure Sectors: Chemical, Energy, Food and Agriculture, Water
and Wastewater Systems
Countries/Areas Deployed: Worldwide
Company Headquarters Location: Germany
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