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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
Publisher:         ICS-CERT
Operating System:  Windows
Impact/Access:     Denial of Service -- Unknown/Unspecified
Resolution:        Patch/Upgrade
CVE Names:         CVE-2017-14023  

Original Bulletin: 

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Advisory (ICSA-17-306-01)


Original release date: November 02, 2017

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CVSS v3 4.9

ATTENTION: Remotely exploitable/low skill level to exploit.

Vendor: Siemens

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.



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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