Victor Nikitin, Vladislav Suchkov, and Ilya Karpov from ScadaX reported coordinated disclosure.

Affected products include:

• firmware variant IEC 61850 for EN100 Ethernet module: all versions prior to v4.33;
• firmware variant PROFINET IO for EN100 Ethernet module: all versions;
• firmware variant Modbus TCP for EN100 Ethernet module: all versions;
• firmware variant DNP3 TCP for EN100 Ethernet module: all versions;
• firmware variant IEC104 for EN100 Ethernet module: all versions;
• SIPROTEC 5 relays with CPU variants CP300 and CP100 and the respective Ethernet communication modules: all versions prior to v7.80;
• SIPROTEC 5 relays with CPU variants CP200 and the respective Ethernet communication modules: all versions.

The EN100 Ethernet modules are used for enabling process communication on either IEC 61850, PROFINET IO, Modbus TCP, DNP3 TCP or IEC 104 protocols via electrical/optical 100 Mbit interfaces on SIPROTEC 4, SIPROTEC Compact and Reyrolle devices. SIPROTEC 5 devices provide a wide range of integrated protection, control, measurement, and automation functions for electrical substations and other fields of application.

As a precondition the IEC 61850‑MMS communication needs to be activated on the affected products or modules.

Specially crafted packets to port 102/tcp could cause a denial-of-service condition in the affected products. Successful exploitation requires an attacker with network access to send multiple packets to the affected products or modules. As a precondition the IEC 61850‑MMS communication needs to be activated on the affected products or modules. No user interaction or privileges are required to exploit the vulnerabilities. The vulnerabilities could allow causing a Denial-of-Service condition of the network functionality of the device, compromising the availability of the system. A manual restart is required to recover the EN100 module functionality.

Vulnerabilities are almost analogous, though CVE-2018-11451 has been classified as more sever (CVSS v3.0 base score 7.5), while CVE-2018-11452 which affects EN100 modules and can be successfully exploited if oscillographs are running is of medium risk (CVSS v3.0 base score 5.9). At the time of advisory publication (11 July 2018) no public exploitation of this security vulnerability was known.

Siemens has released updates for SIPROTEC 5 relays with CPU variants CP300 and CP100 (update to v7.80) and for firmware variant IEC 61850 for EN100 Ethernet module (update to v4.33), is working on updates for the remaining affected products, and recommends to block access to port 102/tcp (e.g. with an external firewall) until fixes are available as well as to protect network access with appropriate mechanisms (e.g. firewalls, segmentation, VPN). [cert-portal.siemens.com]