Case study: Thermostat

Some thermostats have built-in web servers.

Risk

• Turning off someone's heat in the middle of winter?
• Turning on the heat in the summer?
• Run heat and air conditioning simultaneously?

Vulnerability

• Web server uses http other than https:

  1) handshake encryption on Thermostat might be expensive in terms of CPU; 2) how to update web certificates on Theormostat (company doesn't want users to replace thermostats in every 5 years)?

• Unencrypted traffic from the server to the thermostats.
• The passwords are sent in the clear across the Internet, passwords may be stored in clear in bulk on the server.

Privacy issues

• Energy consumption pattern

  Turn off thermostats for a long time, then turn on thermostats $\rightarrow$ possibly just coming back from vacation.

Defenses

• Users can't touch thermostat software (As of notes being taken, Dec 2014).
• Add layering by adding VPN, build users' own access control.

Overall, it's hard to know all the threats. We can see what is made available, and ask who might want it.

Check "gold standard" (Au): Authentication, Authorization, Audit.