From banks to hospitals to the systems that keep the juice flowing to our homes, we are almost entirely dependent on technology. We look at the effect of the five worst 'tech doomsday' scenarios, such as the entire net collapsing, would have on our lives.
Tech doomsday scenario 1: Britain goes dark
News flash: A co-ordinated hack attack on our nation's power grid caused massive blackouts across the UK, leaving more than 60 million people without electricity for days.
The Supervisory Control and Data Acquisition (SCADA) systems that run power plants were built some 40 years ago, when the internet was just a handful of university computers connected via 300-baud modems.
"Back then every power grid system in the world was considered its own island," says Robert Sills, CEO of RealTime Interactive Systems, which provides security solutions for industrial control applications in the US.
"There wasn't technology available to connect them. Now there is."
And the down side of all this connectivity is that once a local grid gets overloaded, others connected to it may tumble like dominoes.
That's what happened in the US August 2003, when overgrown trees and human error triggered a power outage at Ohio's FirstEnergy.
That failure caused a cascade that ultimately left 55 million people in the US and Canada without power.
It doesn't take an act of God or Homer Simpson at the controls to cause a cascading power failure.
It could be a rogue employee seeking revenge - like the software engineer who hacked into an Australian water treatment plant's SCADA system in 1991, releasing 264,000 gallons of raw sewage.
Or it could be an external attacker who gains entry into a SCADA system's maintenance ports via war-dialing, and then uses social-engineering or spear-phishing attacks to gain entry into the network.
Sills says the vast majority of power substations are vulnerable to such an attack.
From there, the attacker simply needs to change a few settings and let the grid's automated fail-safe systems do the rest.
"Right now it's a system that's pretty wide open," says Sills.
"There are any number of ways someone could make unauthorised transactions via routine maintenance. You could create an outage simply by pushing the wrong key."
NEXT PAGE: What could happen
- We look at the likelihood of these doomsday scenarios
- Britain goes dark
- What could happen
- Wall Street gets e-bombed
- How long would it take Wall Street to recover?
- Google is gone
- What could happen if Google goes down
- The net goes down
- What effect would the net going down have on us?
- God strikes back
- Could we recover from an act of God?