P.K. SHARMA

Cyber security intelligence, AI governance, practitioner analysis

Wireless and radio

Satellite time and location receiver (GPS): what it is and how it is attacked

A device that works out where it is, and what the time is, from satellites.

Also known as

  • GPS
  • GNSS
  • GPS clock
  • grandmaster clock
  • timing source

Typing any of them into the editor finds this object.

Why it matters on a security diagram

Far more depends on it than anyone expects. Log timestamps, certificate validity, one-time codes and access schedules all quietly assume the clock is right.

How it gets attacked, and what reduces it

How it gets attacked

  • A faint signal from far away outweighed by a stronger local one, so the receiver reports a time that is not true
  • One receiver supplying time for an entire estate with no fallback of a different kind
  • A clock that steps without raising anything, because nothing monitors time as a signal in its own right

What reduces it

  • Compare against an independent source of a different kind and alert on disagreement
  • Two sources of different kinds is the control; a better single source is not
  • Alert on the step change, not only on the outage

Where it sits

Group
Wireless and radio · The parts of the network that travel through the air, and how far they reach.
Whose side, by default
Ours · Belongs to the organisation the diagram is about.
Catalogue identifier
gnss-receiver

Reviewed . CC BY 4.0.

Others in wireless and radio

The wireless and radio group lists all 11 of them side by side.

Satellite time and location receiver on your own diagram

Open the editor, press N, and type GPS. The object is placed and connected to whatever was selected, and Tab adds the next one already joined to it. Nothing is uploaded: the page is served with a Content Security Policy that forbids the browser from making any outbound request at all.

Open the diagram maker