Flaws in DTM components are threatening security of critical Industrial Control Systems

Researchers at the last Black Hat Europe have presented the results of their research on DTM/FDT components, demonstrating the presence of serious flaws.

The researchers Alexander Bolshev and Gleb Cherbov at Digital Security, have discovered several serious vulnerabilities in industrial components designed to implement the management interface industrial control systems (ICS).

The experts have analyzed the implementation of Field Device Tool / Device Type Manager (FDT/DTM) specification, presenting the results of their research at the Black Hat Europe security conference.

As explained by the researchers within industrial facilities and critical infrastructure, thousands of field devices designed by different vendors coexist, exchange data in a heterogeneous environment using different communication protocols.

The standardization of communication protocols and configuration interfaces between field systems and control systems is the main task of the FDT Group, which is the organization in charge of this important mission, while DTM provides a unified structure for accessing device configuration and operating the devices.

The experts during their presentation explained that DTM makes large use of common technologies such as OLE32, ActiveX, Visual Basic 6.0, .NET, COM and XML, that could be exploited by threat actors to run cyber attacks against industrial systems.

Regarding FDT, FDT 1.2.1 is the version analyzed by the researchers because it is widely used, a Version 2.0 is already available, but the researchers were not able to find a single component to test.

The two researchers tested 114 DTM components, from 24 different vendors, which are used for at least 752 devices that rely on the Highway Addressable Remote Transducer (HART) protocol.

“The HART Communications Protocol (Highway Addressable Remote Transducer Protocol) is an early implementation of Fieldbus, a digital industrial automation protocol. Its most notable advantage is that it can communicate over legacy 4-20 mA analog instrumentation wiring, sharing the pair of wires used by the older system. According to Emerson,^[1] due to the huge installed base of 4-20 mA systems throughout the world, the HART Protocol is one of the most popular industrial protocols today” states Wikipedia on the protocol.

The researchers explained that the research is still ongoing, but meantime they have already discovered 32 vulnerable components actually used more than over 500 devices. The situation is really dangerous if we consider that nearly 50 percent of vulnerable devices are developed by Endress+Hauser, but the company has ignored the alert provided by the researcher as they have explained.

Bolshev and Cherbov have already reported the vulnerability to four vendors and they will send the report to 24 companies by December.

The casuistry of the vulnerabilities detected is varied, and includes XML injection, remote code execution, denial-of-service (DoS) and race condition.

The experts provided a proof of concept for the remote code execution flaw due its severity:

“If you have a vulnerable DTM component, and if you have the field devices that support these components, the attacker could connect to any point on the industrial hierarchy that lies between where the packets from the DTM components go to the device and back. If the attacker could change these packets, he could trigger the vulnerability,” explained Bolshev.

Waiting for the patch is recommended for the adoption of further security measured like firewalls, IDS or any other specific solutions able to recognize the pattern of an ongoing attack.

Security of ICS is very important and Government are aware of critic for the presence of vulnerabilities in critical environments, fortunately specific institutions worldwide are working to spread awareness and provide precious indications and solutions for the protection of these architectures.

Pierluigi Paganini

(Security Affairs – DTM, Critical Infrastructure)