Threats, Vulnerabilities, and Physical Access
This lesson walks one site and asks what could harm it, through which weaknesses, and with what result. The lesson on physical attacks showed how an adversary gets through a door. This one asks what can then be done to the equipment and records inside.
The site is a farm cooperative's grain elevator, described part by part below. This lesson names threats and weaknesses; rating them is left to the lesson on rating physical risk.
| Part of the site | What it holds or does | What the walkthrough found |
|---|---|---|
| Office filing room | Members' signed price contracts | The door has no lock |
| Scale house | The scale terminal, which records each load's weight and so sets each member's pay; the office laptop | Unlocked all day during harvest |
| Dryer shed | The computer that runs the grain dryer | Shed unlocked; two open USB ports on the computer |
| Power | One overhead line from a pole | Feeds every building; no second supply |
Two kinds of threat
Two kinds of threat reach this site. The first is a person with a reason to do harm. A competing grain buyer wants the contract prices. A member may want a load recorded heavier, and someone else may want the harvest stopped.
The second is a natural disaster, here a summer lightning storm. A strike on the overhead line can burn out the dryer computer and destroy the load records on the scale terminal. That's physical damage to computers and data. The same strike stops the scale from weighing trucks, a disruption of a digital service.
Vulnerabilities and compromises
A threat does harm through a weakness, and the walkthrough found one in every part of the site. Here's what a person could do with three of them.
| Weakness | What the adversary does | Compromise |
|---|---|---|
| Filing room with no lock | Photographs the price contracts to sell to a competing buyer | Unauthorized access to a restricted space and to sensitive data |
| One overhead power line | Cuts the line | Disruption of services |
| Scale house left unlocked | Carries off the office laptop | Theft of a physical resource, with the files on it |
| Scale house left unlocked | Changes the recorded weight of one truckload | Unauthorized modification of data |
One unlocked door leads to two different compromises. The stolen laptop leaves an empty desk, but the changed weight leaves nothing missing: the number is wrong, and it goes straight into that member's pay.
Cutting the power
Every device on the site runs on the one overhead line. Cut it, and the scale terminal goes dark, so no truck can be weighed or paid for. The dryer computer stops, and the dryer with it. Nothing is stolen or changed, but no service on the site is available.
The overhead line is the obvious target, but it isn't the only one. The main breaker panel, where the line comes in, would do the same job from indoors, and the transformer on the pole from outside. The lightning storm can hit the same line as the adversary with cutters. At the least it leaves the site dark the same way, and at worst it also burns out the dryer computer and the scale's records.
Access to a room
The filing room holds the site's sensitive information. A buyer who knows every member's price can offer each member slightly more. An adversary in the room can carry the folders out, or copy them.
The adversary in the walkthrough copies the contracts with a phone camera. It's easy to count nothing lost, since every folder is still in its drawer. The prices left the room in the photographs, and the buyer can use them as if the folders had gone.
Access to a device
The dryer computer sits in an unlocked shed with two USB ports on its front. Anyone who walks in can reach both the ports and the machine.
A keylogger slipped in between the keyboard's plug and its port records what the operator types, the sign-in password included. A drive with malware could hand the adversary control of the computer, and so of the dryer it runs.
Smashing the computer stops the dryer just as cutting the line did, but it goes further. The cut line left the computer whole, with its settings and records intact. A smashed computer takes its stored data with it, so the device, its data, and the drying are gone together.