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AUSCERT External Security Bulletin Redistribution
Advisory (ICSA-18-282-05) Siemens SIMATIC S7-1500, SIMATIC S7-1500 Software
Controller and SIMATIC ET 200SP Open Controller
10 October 2018
AusCERT Security Bulletin Summary
Product: Siemens Simatic S7-1500
Siemens Simatic ET 200SP
Operating System: Network Appliance
Impact/Access: Denial of Service -- Remote/Unauthenticated
CVE Names: CVE-2018-13805
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Siemens SIMATIC S7-1500, SIMATIC S7-1500 Software Controller and SIMATIC ET
200SP Open Controller
Original release date: October 09, 2018
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1. EXECUTIVE SUMMARY
o CVSS v3 5.3
o ATTENTION: Exploitable remotely/low skill level to exploit
o Vendor: Siemens
o Equipment: SIMATIC S7-1500, SIMATIC S7-1500 Software Controller and
SIMATIC ET 200SP Open Controller
o Vulnerability: Denial of Service from improper input validation
2. RISK EVALUATION
An attacker with network access to the PLC may be able to cause a
denial-of-service condition on the network stack.
3. TECHNICAL DETAILS
3.1 AFFECTED PRODUCTS
Siemens reports that this vulnerability affects the following products and
o Simatic S7-1500 (incl. F), all versions prior to v2.5 down to and
o Simatic S7-1500 Software Controller all versions prior to v2.5 down to and
o Simatic ET 200SP Open Controller all versions including and after v2.0
3.2 VULNERABILITY OVERVIEW
3.2.1 IMPROPER INPUT VALIDATION CWE-20
An attacker can cause a denial-of-service condition on the network stack by
sending a large number of specially crafted packets to the PLC. The PLC will
lose its ability to communicate over the network. This vulnerability could be
exploited by an attacker with network access to the affected systems.
Successful exploitation requires no privileges and no user interaction. An
attacker could use this vulnerability to compromise availability of the
CVE-2018-13805 has been assigned to this vulnerability. A CVSS v3 base score
of 5.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U
o CRITICAL INFRASTRUCTURE SECTORS: Chemical, Critical Manufacturing, Energy,
Food and Agriculture, Water and Wastewater Systems
o COUNTRIES/AREAS DEPLOYED: Worldwide
o COMPANY HEADQUARTERS LOCATION: Germany
Marcin Dudek, Jacek Gajewski, Kinga Staszkiewicz, Jakub Suchorab, and Joanna
Walkiewicz from National Centre for Nuclear Research Poland reported this
vulnerability to Siemens.
Siemens provides updates to address this vulnerability in these products and
recommends users update to the new version.
o SIMATIC S7-1500 Software Controller: Update to v2.5 or newer:
o SIMATIC S7-1500 incl. F: Update to v2.5 or newer:
Siemens has identified the following specific workarounds and mitigations
users can apply to reduce the risk:
o Restrict network access to affected devices
o Apply cell-protection concept
o Apply defense-in-depth
As a general security measure, Siemens strongly recommends protecting network
access to devices with appropriate mechanisms. In order to operate the devices
in a protected IT environment, Siemens recommends configuring the environment
according to Siemens' operational guidelines for industrial security (https://
following the recommendations in the product manuals.
Additional information on Industrial Security by Siemens can be found at:
For more information on this vulnerability and associated software updates,
please see Siemens security advisory SSA-347726 on their website:
NCCIC recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:
o Minimize network exposure for all control system devices and/or systems,
and ensure that they are not accessible from the Internet.
o Locate control system networks and remote devices behind firewalls, and
isolate them from the business network.
o 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 on the ICS-CERT website in the Technical Information Paper,
ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation
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.
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