Letter: Hacker's challenge

From Clive Semmens

Oona Muirhead of the British Ministry of Defence claims that all its
satellite control systems operate on a “closed network” and cannot be accessed
from an outside telephone line.

While I am quite prepared to believe that they cannot be accessed from a
telephone line, I find the idea of a closed network satellite control system
slightly bizarre. Encrypted, yes, but closed? Scarcely.

The ground station antenna can be large enough to transmit in a narrow beam,
but the satellite antenna cannot be large enough to be very selective, nor can
it transmit a narrow beam. The only difficulty for a potential hacker, apart
from cracking the encryption if any, is getting hold of samples of “uplink”
traffic coming from the ground.

The strength of the uplink signal scattered back from the satellite is almost
certainly too weak to pick up at ground level. But the strength of the leakage
at the ground station sending the signal is almost certainly sufficient.

All a hacker needs to do is find the ground stations. Shouldn’t be too
hard.

csemmens@arm.com