Patching Still Poses Problems for Industrial Controllers, Networking Devices

Two families of critical vulnerabilities that impact operational technology (OT), embedded devices, and network hardware continue to undermine the security of the vast majority of originally affected devices because patching the issues has been glacially slow, according to a new research report by device-security firm Armis.   

Using random sampling, the company checked the patch status of devices vulnerable to flaws affecting seven vulnerable embedded operating systems, including the widespread VxWorks, which it had disclosed in July and October 2019, finding that 97% of devices have not been updated to a patched version of the software. The company also scanned a subset of Cisco network, IP phone, and camera devices for a set of five vulnerabilities disclosed in February 2020, finding 80% of those devices remained vulnerable.

The fact that vulnerable software continues to affect the devices months after the flaws were disclosed underscores the difficulty in patching critical hardware, says Ben Seri, head of research for Armis. 

"These are the types of devices that seem to be hard to patch," he says. "They are in critical applications, and companies often don't want to risk an outage by updating them or taking down the network to fix them."

Vulnerabilities in software used to run operational technology and embedded devices are notoriously difficult to patch and, because they are used in such critical applications, often require complex orchestration to attempt patching. 

The response to the Heartbleed vulnerability in 2014, which affected the OpenSSL cryptographic library, shows the problems complex remediation can have on effective patching rates. Initial patching happened quickly, with the Alexa top 1 million sites driving their vulnerability rate from a maximum of 55% to less than 11% in two days. However, 14% of those patched failed to take another step — changing their private keys — and so remained vulnerable to attack.

"Patching is important, but patching takes time to deploy to mission-critical devices," Seri says. "There is often a reason for them not to get patches, but when you are ready to patch them and take the device offline, it should be easier to complete."

In August, the Defense Advanced Research Project Agency (DARPA) granted $3.9 million to researchers at Purdue University, the University of California at Santa Barbara, and the Swiss Federal Institute of Technology Lausanne (EPFL) to work on a four-year project to improve patching in vulnerable embedded systems and develop automatic and minimal code patching for embedded devices, especially ones for which patches may not be available.

"Many old software components running in these systems are known to contain vulnerabilities; however, patching them to fix these vulnerabilities is not always possible or easy," said Antonio Bianchi, an assistant professor in computer science, in a statement at the time. 

The Armis survey of devices found that two families of vulnerabilities continue to cause significant security gaps for companies. The URGENT/11 vulnerabilities — a set of 11 issues that the cybersecurity firm had previously disclosed in July 2019 — allowed denial-of-service attacks, information leaks, and remote code execution. In October 2019, the company revealed that six other real-time operating systems that supported the IPnet TCP/IP stack were impacted as well: OSE by ENEA, Integrity by Green Hills, ThreadX by Microsoft, Nucleus RTOS by Mentor, ITRON by TRON Forum, and ZebOS by IP Infusion.

While a subset of the vulnerabilities could allow a worm to propagate using exploits, companies continue to be vulnerable, with 97% of the devices originally affected by the security issues remaining vulnerable.

Armis' Seri blames the difficulty in deploying a patch to the millions of devices for the slow patch progress.

The company has also tracked a second set of security issues that its researchers had disclosed in February 2020. Those five vulnerabilities affect Cisco's Discovery Protocol (CDP) and could allow a remote exploit to take control of a device. The company estimates that only 20% of devices that had been vulnerable have been patched. 

"Patching is important, but patching takes time to deploy to mission-critical devices," Seri says. "There is a reason for them not to get patches, but it should be easier to patch them when you do need to take them offline."

Most notably, the aviation and retail industries continue to have high rates of vulnerable devices, with 83% and 90% of vulnerable Cisco devices remaining unpatched. A large number of industrial controllers and networks are also impacted by the two families of issues, Seri says.

"We do see a lot of manufacturing is being targeted by attacks as well," he says. "So the high percentage of vulnerable devices impacted and the low frequency of patching puts these devices in the highest risk category."