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             AUSCERT External Security Bulletin Redistribution

                Siemens SIMATIC, SINUMERIK, and PROFINET IO
                               21 March 2018


        AusCERT Security Bulletin Summary

Product:           Siemens SIMATIC, SINUMERIK, and PROFINET IO
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2018-4843  

Original Bulletin: 

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Advisory (ICSA-18-079-02)
Original release date: March 20, 2018

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CVSS v3 5.3

ATTENTION: Exploitable from an adjacent network

Vendor: Siemens


Vulnerability: Improper Input Validation


Siemens reports that the vulnerability affects the following products:

    SIMATIC CP 343-1 Advanced: All versions,
    SIMATIC CP 343-1 Standard: All versions,
    SIMATIC CP 443-1 Advanced: All versions,
    SIMATIC CP 443-1 Standard: All versions,
    SIMATIC S7-1500 Software Controller incl. F: All versions prior to V1.7.0,
    SIMATIC S7-1500 incl. F: All versions prior to V1.7.0,
    SIMATIC S7-300 incl. F and T: All versions,
    SIMATIC S7-400 H V6: All versions,
    SIMATIC S7-400 PN/DP V6 Incl. F: All versions prior to V6.0.7,
    SIMATIC S7-400 PN/DP V7 Incl. F: All versions,
    SIMATIC S7-410: All versions prior to V8.1,
    SIMATIC WinAC RTX 2010 incl. F: All versions,
    SINUMERIK 828D: All versions,
    SINUMERIK 840D sl: All versions, and
    Softnet PROFINET IO for PC-based Windows systems: All versions.


Successful exploitation of this vulnerability could result in a 
denial-of-service condition requiring a manual restart to recover the system.


Siemens has provided the following updates for mitigations:

    SIMATIC S7-1500 Software Controller incl. F: Update to V1.8.5 or newer, 
    which can be located here:

https://support.industry.siemens.com/cs/ww/en/view/109478528 (link is external)

    SIMATIC S7-1500 incl. F: Update to V1.8.5 or newer, which can be located here:

https://support.industry.siemens.com/cs/ww/en/view/109478459 (link is external)

    SIMATIC S7-400 PN/DP V6 Incl. F: Update to V6.0.7, which can be located here:

https://support.industry.siemens.com/cs/ww/en/view/109474874 (link is external)

    SIMATIC S7-410: Update to V8.1, which can be located here:

https://support.industry.siemens.com/cs/ww/en/view/109476571 (link is external)

For all other affected products, Siemens has identified the following specific 
workarounds and mitigations that users can apply to reduce the risk, refer to:

    Apply cell protection concept.
    Use VPN for protecting network communication between cells.
    Apply defense-in-depth.

Additional information is available at:

(link is external):

As a general security measure, Siemens strongly recommends to protect network 
access to devices with appropriate mechanisms. In order to run the devices in a 
protected IT environment, Siemens particularly recommends to configure the 
environment according to Siemens’ operational guidelines for industrial 
security, and to follow the recommendations in the product manuals. Additional 
information on industrial security by Siemens can be found at:

https://www.siemens.com/industrialsecurity (link is external)

For more information on this vulnerability and associated software updates, 
please see Siemens security notification SSA-592007 on their website:

https://www.siemens.com/cert/advisories (link is external)

NCCIC recommends 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.

NCCIC reminds organizations to perform proper impact analysis and risk assessment 
prior to deploying defensive measures.

NCCIC 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 NCCIC Technical Information Paper, ICS-TIP-12-146-01B--Targeted Cyber 
Intrusion Detection and Mitigation Strategies, that is available for download 
from the ICS-CERT website.

Organizations observing any suspected malicious activity should follow their 
established internal procedures and report their findings to NCCIC for tracking 
and correlation against other incidents.

No known public exploits specifically target this vulnerability. High skill level 
is needed to exploit.



Responding to a PROFINET DCP request with a specially crafted PROFINET DCP packet 
could result in a denial-of-service condition of the requesting system. This 
vulnerability could be exploited if the attacker is located on the same Ethernet 
segment (OSI Layer 2) as the targeted device.

CVE-2018-4843 has been assigned to this vulnerability. A CVSS v3 base score of 5.3 
has been calculated; the CVSS vector string is (AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H).


Siemens ProductCERT reported this vulnerability to NCCIC.


Critical Infrastructure Sectors: Chemical, Critical Manufacturing, Energy, Food 
and Agriculture, Water and Wastewater Systems.

Countries/Areas Deployed: Worldwide

Company Headquarters Location: Germany

Contact Information

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

Email: NCCICCUSTOMERSERVICE@hq.dhs.gov (link sends e-mail)
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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