Siemens created new firmware to mitigate a web security vulnerability in its SCALANCE M-800 and S615 modules, according to a report with ICS-CERT.
SCALANCE M-800/S615: All versions before V4.02 suffer from the remotely exploitable vulnerability, which ended up reported directly to Siemens by Alexander Van Maele and Tijl Deneut from HOWEST.
Exploitation of this vulnerability could allow an attacker in a privileged network position to obtain web session cookies under certain circumstances.
Siemens is a multinational company headquartered in Munich, Germany.
The affected products are SCALANCE M-800/S615 modules. SCALANCE M industrial routers are industrial-grade routers used to connect networked industrial components.
This product line provides a Web interface to manage the router configuration. The SCALANCE S firewall protects trusted industrial networks from untrusted networks and provides additional security functionality, e.g., VPN tunnels==2E.
SCALANCE M-800/S615 modules see action across several sectors including chemical, critical manufacturing, dams, defense industrial base, energy, food and agriculture, government facilities, transportation systems, and water and wastewater systems.
Siemens said these products see use on a global basis.
The integrated web server delivers session cookies without the “secure” flag. Modern browsers interpreting the flag would mitigate potential data leakage in case of clear text transmission.
CVE-2016-7090 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 4.0.
No known public exploits specifically target this vulnerability. In addition, crafting a working exploit for this vulnerability would be difficult.
Siemens provides firmware version V4.2 for SCALANCE M-800/S615 to mitigate this vulnerability. Click here to download the firmware version.
Siemens recommends users protect network access to the management interface of SCALANCE M-800/S615 modules with appropriate mechanisms. Siemens also advises users configure the operational environment according to Siemens overview of the operational guidelines for Industrial Security (with the cell protection concept):
For more information on this vulnerability and more detailed mitigation instructions, please see Siemens Security Advisory SSA-342135.