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AUSCERT External Security Bulletin Redistribution
Advisory (ICSA-17-306-01) Siemens SIMATIC PCS 7 Improper Input Validation
3 November 2017
AusCERT Security Bulletin Summary
Product: Siemens SIMATIC PCS 7
Operating System: Windows
Impact/Access: Denial of Service -- Unknown/Unspecified
CVE Names: CVE-2017-14023
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Siemens SIMATIC PCS 7
Original release date: November 02, 2017
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CVSS v3 4.9
ATTENTION: Remotely exploitable/low skill level to exploit.
Equipment: SIMATIC PCS 7
Vulnerability: Improper Input Validation
The following versions of SIMATIC PCS 7, a distributed control system, are
- -V8.1 prior to V8.1 SP1 with WinCC V7.3 Upd 13, and
- -V8.2 all versions.
Successful exploitation of this vulnerability could allow a remote
authenticated attacker to crash services on the devices.
Siemens has released the following updates:
V8.1: Update to V8.1 SP1 with WinCC V7.3 Upd 13 which can be obtained from:
https://support.industry.siemens.com/cs/ww/en/view/109746452 (link is
Siemens is currently working on updates for the remaining affected versions
and recommends that affected users:
- -Apply cell protection concept,
- -Use VPN for protecting network communication between cells, and
- -Apply Defense-in-Depth.
Siemens also strongly recommends that users protect network access to the
SIMATIC PCS 7 with appropriate mechanisms by configuring the environment
according to operation guidelines that can be found at:
https://support.industry.siemens.com/cs/ww/en/view/60119725 (link is
For more information on this vulnerability and more detailed mitigation
instructions, please see Siemens Security Advisory SSA-523365 at the following
http://www.siemens.com/cert/en/cert-security-advisories.htm (link is external)
NCCIC/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.
IMPROPER INPUT VALIDATION CWE-20
The improper input validation vulnerability has been identified, which may
allow an authenticated remote attacker who is a member of the administrators
group to crash services by sending specially crafted messages to the DCOM
CVE-2017-14023 has been assigned to this vulnerability. A CVSS v3 base score
of 4.9 has been assigned; the CVSS vector string is
Sergey Temnikov and Vladimir Dashchenko of Kaspersky Labs reported the
vulnerability to Siemens.
Critical Infrastructure Sectors: Chemical, Energy, Food and Agriculture, and
Water and Wastewater Systems
Countries/Areas Deployed: Worldwide
Company Headquarters Location: Germany
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