Re: First real-world SCADA attack in US

[Jay Ashworth <jra () baylink com>]

----- Original Message -----
> From: "Brett Frankenberger" <rbf+nanog () panix com>

> The typical implementation in a modern controller is to have a separate
> conflict monitor unit that will detect when conflicting greens (for
> example) are displayed, and trigger a (also separate) flasher unit that
> will cause the signal to display a flashing red in all directions
> (sometimes flashing yellow for one higher volume route).
>
> So the controller would output conflicting greens if it failed or was
> misprogrammed, but the conflict monitor would detect that and restore
> the signal to a safe (albeit flashing, rather than normal operation)
> state.

"... assuming the *conflict monitor* hasn't itself failed."

There, FTFY.

Moron designers.

Cheers,
-- jra
-- 
Jay R. Ashworth                  Baylink                       jra () baylink com
Designer                     The Things I Think                       RFC 2100
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