ICS Network Managers: Time for a Wake-Up Call

Positive Technologies has come up with a research report that anyone with responsibility for a network supporting an industrial facility should find worrisome.

In the report, "Industrial Companies: Attack Vectors," researchers note that attackers were able to penetrate the network perimeters of 73% of industrial organizations. In 82% of their tests, an attacker could gain a foothold and then leverage it to access the broader industrial network, which contained Industrial Control System (ICS) equipment.

PT researchers described the networks used to control equipment in manufacturing, energy and the like were generally secured in a different manner than were office networks.

The reason, according to the report, is that organizations are afraid to make any changes such as patches or upgrades that might cause downtime. So, these businesses try to compensate for this by placing ICS components on a separate network, isolating them or air gapping them entirely from internet-connected corporate systems. (See New Vulnerability Puts Industrial Systems at Risk.)

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At first glance, that is a reasonable approach.

However, PT found that such efforts fell short in practice, leaving attack vectors still open.

The paper included SSH, Telnet, RDP and other administration interfaces that were exposed. Moreover, 91% of the organizations relied on dictionary passwords for privileged users.

The corporate networks that were connected to ICS systems also exposed database management system (DBMS) interfaces (82% of total tested), vulnerable software (64%), use of insecure protocols (64%), arbitrary file upload flaws (45%), remote command execution vulnerabilities (36%) and excessive software and user privileges (36%).

Those corporate networks also had flaws in network segmentation and traffic filtering that could help an attacker to move laterally within the system.

PT found that in two thirds of the cases, corporate networks contained special control channels for the ICS network that bypassed the demilitarized zone (DMZ) which should separate the two.

Not only that, in 45% of the tested networks there was poor traffic filtering between the two networks. Additionally, there may have been no DMZ between the networks (18%) or no network segmentation (18%).

PT warned that companies might think that having a dedicated channel for remote control of gateway servers is less risky, since an attacker would need to obtain access to specific workstations in the corporate information system. But researchers strongly warn that it is only an illusion that such a solution is secure. Specifically, they found that this method of penetrating an industrial network was successfully demonstrated in most of their tests.

Network segmentation was not found to be a cure-all, since firewalls could be accessed with admin privileges and then changing parameters. This then allows a connection from some malicious device.

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The passwords that would allow this firewall changing to be done were found to be weak or poorly protected. They may be stored on the corporate side in plain text, or the firewalls themselves were vulnerable to a brute-force attack.

Paolo Emiliani, Industry and SCADA research analyst at Positive Technologies, took an overview of the underlying problems in a statement:

"Security is not just a technical problem, but an organizational one. On average, each company we tested had at least two penetration vectors. A company might have a number of facilities very far apart from each other, with only a handful of security staff to go around. This puts security staff in a difficult position: they have to enable remote desktop access to get their job done, even though this opens security holes. Compounding the problem, different teams may share responsibility for securing their organizations’ network and industrial systems."

This report should be a wake-up call for all ICS system operators to rethink their overall security practices. Some downtime and changes may be needed to protect their true goals.

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— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.