Siemens has a fix and a mitigation plan for an insufficiently protected credentials and a man-in-the-middle vulnerabilities in its LOGO! Product, according to a report with ICS-CERT.
All versions of LOGO!8 BM suffer from the remotely exploitable vulnerabilities, discovered by Maxim Rupp.
Successful exploitation of these vulnerabilities could allow an attacker to hijack existing web sessions.
No known public exploits specifically target these vulnerabilities. However, an attacker with low skill level could leverage the vulnerabilities.
In one vulnerability, an attacker with network access to the integrated web server on Port 80/TCP could obtain the session ID of an active user session. A user must be logged in to the web interface. Siemens recommends users use the integrated webserver on Port 80/TCP only in trusted networks.
CVE-2017-12734 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 7.5.
In addition, an attacker who performs a man-in-the-middle attack between the LOGO! and other devices could potentially decrypt and modify network traffic.
CVE-2017-12735 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 7.4.
The product sees use mainly in the commercial facilities and transportation systems sectors. It also sees action on a global basis.
Siemens provides LOGO!8 BM FS-05 with firmware Version V1.81.2, which fixes the first vulnerability.
Siemens recommends applying the following mitigations for users with existing installations, and for mitigation of the second vulnerability:
• Configure the environment according to the recommendations in the user manual
• Apply cell protection concept
• Use VPN for protecting network communication between cells
• Apply Defense-in-Depth
As a general security measure, Siemens recommends protecting network access to the devices with appropriate mechanisms. Siemens advises configuring the environment according to Siemens operational guidelines in order to run the devices in a protected IT environment.
For more information on these vulnerabilities and more detailed mitigation instructions, please see Siemens Security Advisory SSA-087240 at the following location.