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Testing strategy for Controllers

Controllers are an essential part of ICS (Industrial Control Systems) network. Generally they are interface to many field devices such as sensors and placed within closed network. Exposing them outside world may be disastrous and they can be configured/ mis- configured to carry put attacks which can have dangerous impact on human being's life and safety.

So, it's necessary to do a security assessment of ICS networks to uncover potential vulnerabilties.
In brief, to test a controller we need to:
  • Understand the entire architecture- the platform, technologies, protocol it understands. Do a quick threat modeling here.
  • Review Network architecture, see how the controller is placed, ideally it should not be reachable from internet.
  • Firmware testing: Most of the controllers have embedded systems on them. Do a firmware testing here-
  • De compiling, modifying, patching, looking for hard coded sensitive credentials. How the firmware is uploaded/ downloaded- how secure is the mechanism.
  • Do host level review- Check if the controller is running any unnecessary/ insecure services, open ports, older software versions etc.
  • If web interface is enabled, do a testing from web app level security assessment.
  • If controller is using any proprietary or open source protocol, read the manual and try to understand the stack, what all security issues were discovered historically, what all tools are available in market to test them.
  • Get in touch with developers who work day in out with the technology.


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