Defending Industrial Ethernet Switches Is Not Easy, But Doable

BLACK HAT USA -- Las Vegas -- A team of researchers who found a slew of vulnerabilities across five models of Industrial Ethernet Switches said that the SCADA community can monitor for and respond to vulnerabilities in their network devices and do not have to necessarily depend on vendors to do the defense.

The team found 11 vulnerabilities ranging from cross-site scripting attacks to default key manipulation across five families of network devices from four different vendors -- Garrettcom, GE, Opengear, and Siemens.

Many in the Industrial Control System (ICS) and Supervisory Control and Data Acquisition (SCADA) community assume that their massively vulnerable infrastructure can only be fixed by the vendors, according to Éireann Leverett, who works with the University of Cambridge Centre for Risk Studies. 

“We need vendors to do better. We want them to do better,” Leverett said. “But we as a community, especially in the ICS and SCADA community don’t need vendors to do defense.  A lot of the attacks and vulnerabilities being demonstrated, you can easily monitor for them and easily detect and respond to them.  It is really about empowering the community versus feeling helpless,” he said.

“A lot of these switches have configurations that you can turn on or modify and that will strengthen your security. A lot of work can be done by yourself without harassing the vendor to say, ‘Look we need this fixed,” Colin Cassady, a security consultant with IOActive, said.

Cassady, Leverett, and Robert Lee, co-founder of Dragos Security LLC, presented their findings during a press briefing and later in more detail during a session titled Switches Get Stitches.

Industrial Control Systems have become an area of increasing concern for cybersecurity as the world has become more connected and information technology and operational technology are more intertwined.  The Industrial Ethernet Switches are used in environments such as substations, factories, refineries, ports, or other homes of industrial automation.  If attackers are able to compromise these switches, malicious firmware could be inserted to manipulate live processes such as the shutting down of a plant or a nuclear reactor.

Since industrial system protocols lack authentication or cryptographic integrity, the researchers focused on attacking the management plane of the switches. The discovered vulnerabilities were reported to the vendors.  Patching of ICS/SCADA devices by vendors can take from months to a year.

That is why the researchers were surprised by Opengear’s turnaround time after a vulnerability was disclosed in one of its family of switches.  Leverett reported an old vulnerability listed in the National Vulnerability Database as CVE-2006-5229. The vulnerability, associated with OpenSSH portable 4.1 on SUSE Linux, and possibly other platforms and versions, allows remote attackers to determine valid usernames via timing discrepancies in which responses take longer for valid usernames than invalid ones, according to the NVD. 

Opengear officials responded with a fix within a week, in “sprint time,” compared to the other vendors, Cassady noted.  It took Siemens six months to respond with fixes to various vulnerabilities.

“It is great when Opengear comes back and says, ‘Not only are we not going to sue you for exploiting these vulnerabilities, but here is another [device] find the vulnerabilities’” Lee said.  “That is great for the research community.”  But not every vendor company is like that.

As a result, “we need engineers, operators, and operational technology security folks to take a look at the network, understand the environment they are in, and monitor it for these occurrences,” Lee said.

“Our greatest strength in the community, the thing that gives us the most defensible territory is folks understanding their environment and abnormalities and changes in it,” Lee noted.  Network architects, operational people and process engineers who really know their environments can spot adversaries very quickly. This work can be difficult given process and time management constraints, he acknowledged.

“It is not an easy thing, but it is a doable thing,” Lee said.

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