**ATTENTION:**Remotely exploitable/low skill level to exploit
Vendor: Siemens
Equipment: SIMATIC
Vulnerability: Authentication Bypass
This updated advisory is a follow-up to the updated advisory titled ICSA-17-045-03A Siemens SIMATIC Authentication Bypass that was published June 15, 2017, on the NCCIC/ICS-CERT web site.
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Siemens reports that the vulnerability affects the following software applications used for central user administration:
The following products include affected versions of SIMATIC Logon:
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Successful exploitation of this vulnerability could allow attackers to circumvent user authentication under certain conditions.
Siemens provides SIMATIC Logon V1.5 SP3 Update 2 and recommends that users update to the new version. Customers that use recent versions of SIMATIC WinCC, SIMATIC PCS 7, SIMATIC IT, or SIMATIC PDM can install the new version of SIMATIC Logon without an update of these products as described in the compatibility note that can be accessed via the download link below:
<https://support.industry.siemens.com/cs/ww/en/view/109744966>
For more information on this vulnerability and more detailed mitigation instructions, see Siemens Security Advisory SSA-931064 at the following location:
<http://www.siemens.com/cert/en/cert-security-advisories.htm>
As a general security measure Siemens strongly recommends configuring the environment according to Siemensβ operational guidelines in order to run the devices in a protected IT environment.
<https://www.siemens.com/cert/operational-guidelines-industrial-security>
NCCIC/ICS-CERT recommends that users take defensive measures to minimize the risk of exploitation of this vulnerability. Specifically, users should:
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 ICSβCERT Technical Information Paper, ICS-TIP-12-146-01BβTargeted 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. High skill level is needed to exploit.
An attacker with knowledge of a valid user name, and physical or network access to the affected system could bypass the application-level authentication.
CVE-2017-2684 has been assigned to this vulnerability. A CVSS v3 base score of 9.0 has been calculated; the CVSS vector string is (AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H).
Critical Infrastructure Sectors: Chemical, Energy, Food and Agriculture, and Water and Wastewater Systems
Countries/Areas Deployed: Deployed worldwide
Company Headquarters Location: Germany
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