
The Great Brazilian Sat-Hack Crackdown (2009) - wglb
https://www.wired.com/2009/04/fleetcom/
======
b1r6
So these satellites are no more complex than the amateur radio birds which
function as simple FM repeaters?! Typically they'll have an uplink in the 2m
band, and maybe a downlink in 70cm band, or the other way around. How can a
military satellite be so casual in it's decision to relay audio? You'd think
some authentication method would have been built in. I guess not?

~~~
jandrese
Almost all comm sats are just bent pipes. Collisions are avoided via planning
but that's just a gentleman's agreement at the end of the day. If you're
watching with a spectrum analyzer and a decent dish it's pretty easy to see
which transponders are currently idle.

The downside of course is that once you start hitting a satellite with a
signal they know exactly where you are and the operators will call the cops on
you. Your signal is not only potentially interfering with someone who paid for
the transponder, but it also impacts their energy budget.

I've been told that if you rent a transponder it's important to put a signal
up on it pretty quickly, otherwise pirates will attempt to "borrow" it from
you, and they can be hard to evict.

~~~
samstave
How do I get more info on this? This sounds like a fantastic subject to learn
about.

~~~
ablation
Seconded. The article and these comments leave me wanting more!

~~~
jandrese
What I know about this comes from some training I took for my job. The
training came from the equipment vendor, but the instructor was also an
operator so he knew the ins and outs of the system.

There is a lot to cover, from calculating link budgets, scramble codes
(related to anti-jam), waveforms, pointing a dish, calculating frequencies,
reading channel allocation docs, tradeoffs of different frequency bands,
etc... However, the basics are pretty basic. You modulate a series of bits
onto a carrier at a specific frequency and radiate it at a specific point in
the sky. The transponder on the satellite amplifies the signal, shifts it a
fixed number of Mhz, and retransmits it back towards the Earth.

There are some satellites that act like flying routers and actually decode the
packet back into bits before re-encoding it for transport, but generally the
added complexity has made this approach unpopular. One constellation that does
this is Iridium, because it then forwards packets between satellites until it
can be downlinked to the ground.

~~~
wglb
Routing satellite to satellite sounds like a complex routing problem, no? Or
are such routes computed before signal goes up?

~~~
rtkwe
Not particularly. They're all in fixed known orbits so each satellite would
know at any given time where all the other satellites in it's constellation
will be so it can know what satellites will have the best signal between it
and the downlink. With that all you really need is for the phones to ping the
satellites every couple minutes while on to update the what satellites are
over head of phone X. (You could even be clever and cheat a little by figuring
out the rough coordinates of each handset and then figure out roughly what
satellites would be near overhead too since handsets generally don't move very
quickly.)

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Tepix
The design life of the system was five years, according to
[https://space.skyrocket.de/doc_sdat/fltsatcom-2.htm](https://space.skyrocket.de/doc_sdat/fltsatcom-2.htm)

I'm sure the military has better ways to communicate these days. Perhaps the
access should be allowed?

~~~
moftz
Why give up access bandwidth on a satellite meant for last resort kinds of
communications? The satellite isn't self sufficient so someone in the military
has to adjust it in space. There might be older pieces of equipment out there
still using the satellite so having a bunch of random people taking up
bandwidth and not following the channel allocation. It's better to just
enforce the rules that already exist to make sure that the resources are
always available.

------
danilocesar
This was 10 years ago. I hope that USMs are using better tools by now..

~~~
jandrese
Those birds are probably still in the air. Few comm satellites are full
processing anyway so there is no mechanism to enforce it up in the sky. Normal
enforcement is via having the cops show up at your door and ask why you are
stealing the US Government's power and interfering with military operations.

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codetrotter
> When the user's location is stable, the signal can be triangulated. That's
> how the Defense Department got the coordinates to feed Brazilian authorities
> in March's raids.

Of course. But specifically how? With satellites in space? Or antennas on
ground? If on ground, where? And if on ground, for triangulating these
specific people or for other purposes as well? And if sattelites space, the
same sattelites that are relaying the signals, or separate sattelites?

~~~
CalChris
The ground transmission antenna is sending a high gain signal towards the
satellite. But that doesn't mean that _all_ of the energy is directed there.
Some gets scattered isotropically and a signal detection plane could
triangulate off that.

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gcb0
this thread is amusing. so many people on HN should go get their amateur radio
licenses and stop comparing a layer 1 radio connection to their layer 7+ they
use in the browser.

~~~
b1r6
I do indeed have my license. Only a Tech but even that level gets you access
to the VHF/UHF birds.

Are you saying we shouldn't expect a military satellite to have _some_
semblance of simple authentication?

It sounds like what they built was literally a simple repeater. If that's the
case, they shouldn't have a problem with this "unauthorized use," because by
design, there is _no such thing_.

(The preceding assumes the pirate is licensed to transmit in the 1.25m band
that the article noted as the uplink.)

~~~
sterlind
Look, they're bent pipes because it's faster, cheaper and more scalable. If
you do authentication, you need the satellite to process and validate each
packet before repeating it. That means that suddenly you need a processor - a
beefy one, to handle so many signals at once and understand the modulation,
and you have a delay between receiving and sending. You also have new failure
modes to worry about, new components that can fail, protocol lock-in,
maintenance, etc.

Bent pipes are perfect. Not everything needs to be overengineered to hell. A
handful of pirates aren't a big enough deal to boil the ocean with a DSP. And
assuming that the signal is Manchester-coded, you can defeat the pirates in
future models with a simple analog filter to remove their noise.

~~~
b1r6
I now see what you're saying. I guess it's just funny that I could defeat
military comms by simply leaving my mic open and bumping the dial to the right
frequency...

It sounds like back in the day what I described above wasn't an issue.

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anovikov
Idk how the military ever expected to be able to use these satellites in
wartime. First thing enemy will do is saturate them with fake signals from
small and cheap battery-powered transmitters just left alone in random places
(so targeting them with anti-radiation missiles would make little sense).
Sounds like someone has been unbelievably dumb.

~~~
jandrese
Anti-jamming is a thing. As you note jamming satellite comms is certainly
possible, but it paints a great big target on your back. And the US military
has no problem using a million dollar missile to blow up a $500 jammer.

~~~
LeftTurnSignal
I've been toying with the idea of getting into ham radio type stuff, so it's
always been interesting to me.

After working with the local detectives / police, it isn't "very" difficult to
find where a jammer is. /I never got the chance to work directly with them on
that issue though, but they said it's happened once before.

Anyway, it took them one call to Verizon and less than a day later they found
who was jamming one area. Did the police thing, and no more jamming. They had
the pull because no one could call 911 with a cell phone in that area, and
when the squads were out, they'd lose reception around that area too. Both big
no nos if you want to stay hidden.

I can imagine if it's a country with adequate resources, it would not be much
of an issue.

~~~
velosol
And if you think you're clever by using a jammer while mobile, you're in for
some financial pain on top of any legal issues you create for yourself.

[https://www.fcc.gov/document/fcc-fines-florida-
driver-48k-ja...](https://www.fcc.gov/document/fcc-fines-florida-
driver-48k-jamming-communications)

