Exercise Dark Turbine

The cleanest kill is the one where the machine destroys itself on its own momentum. By working the timing differences between the mismatched controllers in a multivendor plant, an adversary nudges the rotational synchronisation of the city’s main generators out of true. Nothing is deleted. The steel is simply persuaded to chew through its own bearings.

The control room

  • Unseen University Power and Light Co.: holding the disaster-recovery runbooks and discovering that every automated failover it has ever tested assumes a network that is cooperating.

  • The Royal Bank: whose automated mints and vault mechanisms flinch each time the generator rhythm stumbles. A day of erratic voltage is a day the vault doors cannot be trusted to lock or to open.

  • The Civil Observers’ Society: which reverse-engineers a captured gateway update and finds that the anonymous connections opened during the last emergency upgrade were never closed.

  • The Civic Defence Establishment: facing the question of whether to post physical guards on substations that are failing for reasons no guard can see.

  • The Circle Sea Arrangement: whose shared threat picture has no category for an attack that looks exactly like a poorly maintained bearing until the machine splits in half.

The first signs

The first sign is acoustic, not digital. Senior mechanics notice a harmonic groan in the foundations of the turbine house, a frequency with no natural source. On the monitors the generator speed wanders by less than half a per cent, and the tools file it as routine load balancing.

The language changes when the first bearing housing shears through four inches of dwarven iron. The latency logs show out-of-phase synchronisation commands sent to individual controllers at precisely chosen intervals, using the generators’ own mass against them. The network is entirely up. The trouble is that the plant speaks several protocols at once, and nothing stops two of them from issuing contradictory orders to the same shaft.

Decision points

  • Whether to segment the plant mid-incident. Cutting the traffic between the operator stations and the controllers stops the phase attack and blinds the engineers to the real state of the spinning rotors at the same stroke.

  • Whether to invoke the manual fallback. Dropping the plant to fully mechanical governance, five hundred people with clipboards and brass gauges, strips the digital layer of its leverage and reduces the city to pre-industrial output. It works. It is also an admission, in public, of how far the machine had been trusted.

  • What to tell the arrangement, given that the honest description, an attack indistinguishable from wear until the steel fails, is the one its shared categories cannot hold.

The quiet hides the attack inside tolerance. As long as the deviation stays under the threshold the monitors treat as noise, the damage accrues for free, and by the time the groan is loud enough to name, the bearings have already paid for it.

When it breaks

  • The historian is wiped. As the turbines approach failure, the process history is dropped record by record, so the city loses its machinery and the evidence of how at the same moment.

  • The backups have already learned the attack. The synchronisation logic migrated to the emergency arrays during the first hour’s housekeeping, so the instant the main grid drops and the backups take the load, they enter the same self-destructive rhythm and tear themselves apart on cue.

Into the bearings