Siemens has released a firmware update to address a vulnerability affecting RUGGEDCOM switches, devices designed to operate in harsh environments.
The security hole, reported by Stephen Craven of the Tennessee Valley Authority (TVA), exists in the ROS operating system running on some RUGGEDCOM switches. The flaw can be exploited by an attacker with access to one virtual LAN (VLAN) to bypass isolation and access devices in a different VLAN. This is possible because affected switches include an IP forwarding feature that cannot be disabled by users.
Siemens has pointed out that an attack can only be carried out if the device has IP addresses configured on multiple VLANs. That is the only way traffic can be routed between the VLANs.
The flaw affects the ROS operating system running on layer 2 switches. The security hole exists in ROS versions starting with 3.8.0 and prior to 4.2.0, but Siemens has pointed out that RMC, RP110 and RS950G devices are not impacted.
The vulnerability has been assigned the CVE identifier CVE-2015-6675, and a CVSS score of 4.3, which puts it in the “medium” severity category.
Siemens addressed the issue with the release of ROS 4.2.0, which allows users to disable IP forwarding. Organizations using affected RUGGEDCOM switches are advised to update to the latest version and disable IP forwarding if the feature is not needed. As a workaround, ICS-CERT recommends removing IP addresses from the VLAN.
“As a general security measure Siemens strongly recommends to protect network access to ROS devices with appropriate mechanisms. It is advised to configure the environment according to our operational guidelines in order to run the devices in a protected IT environment,” Siemens said in its advisory.
This is not the first patch released by Siemens for RUGGEDCOM devices this year. In February, the company announced releasing a firmware update for WIN devices to fix a couple of critical vulnerabilities. Siemens also released ROS firmware updates in July to patch the POODLE vulnerability.
The most widely publicized security hole identified in RUGGEDCOM devices was disclosed in 2012, just months after Siemens announced acquiring Toronto-based RuggedCom. A researcher reported at the time that he had discovered a backdoor in the company’s products. The flaw was patched only after the researcher publicly disclosed his findings.
The existence of the backdoor came to light several months before former NSA contractor Edward Snowden started leaking classified documents revealing that the intelligence agency had been working with device vendors on creating backdoors in their products.
Related: Learn More at the ICS Cyber Security Conference