Adversaries may move onto systems, such as those separated from the enterprise network, by copying malware to removable media which is inserted into the control systems environment. The adversary may rely on unknowing trusted third parties, such as suppliers or contractors with access privileges, to introduce the removable media. This technique enables initial access to target devices that never connect to untrusted networks, but are physically accessible. Operators of the German nuclear power plant, Gundremmingen, discovered malware on a facility computer not connected to the internet. (Citation: Kernkraftwerk Gundremmingen April 2016) (Citation: Trend Micro April 2016) The malware included Conficker and W32.Ramnit, which were also found on eighteen removable disk drives in the facility. (Citation: Christoph Steitz, Eric Auchard April 2016) (Citation: Catalin Cimpanu April 2016) (Citation: Peter Dockrill April 2016) (Citation: Lee Mathews April 2016) (Citation: Sean Gallagher April 2016) (Citation: Dark Reading Staff April 2016) The plant has since checked for infection and cleaned up more than 1,000 computers. (Citation: BBC April 2016) An ESET researcher commented that internet disconnection does not guarantee system safety from infection or payload execution. (Citation: ESET April 2016)
Make configuration changes related to the operating system or a common feature of the operating system that result in system hardening against techniques.
M0934Limit Hardware InstallationBlock users or groups from installing or using unapproved hardware on systems, including USB devices.
M0942Disable or Remove Feature or ProgramRemove or deny access to unnecessary and potentially vulnerable software to prevent abuse by adversaries.
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