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Fascinating, thanks for your comment! How would an attack like this look? Would every siren need to receive this broadcast then, and if so wouldn't that put the

Fascinating, thanks for your comment! How would an attack like this look? Would every siren need to receive this broadcast then, and if so wouldn't that put the broadcast power required to pull this off above most consumer gear? If that's the requirement, isn't that a poor design? I knock out one or two points in the city and the sirens are unusable?

jcrawfordor 10y ago
If my guess that they use their POCSAG system is right, they have four transmitter sites licensed to 350 watts each. This is beyond inexpensive equipment, but not beyond what you can buy from a ham radio shop and then 'unlock', for example. But of course it's a paging system, so the goal is strong one-way coverage to small devices in buildings and such. The sirens are all outdoors and probably all have generous fixed antennas installed, so you wouldn't need nearly as much power to get a message to them. I assumed that the hackers injected their command via radio, which I still think is likely based on getting the FCC involved, but with POCSAG involved there's definitely another possibility. A lot of pager systems might have a fairly exposed way to send in messages - a phone number you can call, an email address, perhaps a poorly secured web interface. The hackers might have figured out what pager numbers the sirens respond to by listening in and then sent their message via "legitimate" means like an email-to-pager gateway.
zorm 10y ago
There were mentions of the repeater system last night, so my guess is they transmitted weakly somewhere and the repeater happily repeated it out to activate all the sirens. You can do this pretty trivially with HAM gear, although some may require small modifications to allow transmitting on the necessary frequencies. You can also often buy the equipment on ebay ready to go.
- cyberpunk 10y ago
  I didn't see that got a link? I sort of felt (in my ignorance of such systems) that this would have been somehow relayed / repeated instead of being a broadcast across an entire city but I didn't want to speculate as I'm clueless on this kind of tech. I know it's a nuisance, but this is the sort of thing I daydreamed about doing when I was 13 so I can't help but be kind of entertained by it (at least while the only fallout appears to be knocking people out of bed).
- jcrawfordor 10y ago
  The city has licenses for repeater-equipped public service frequencies, so it's definitely a possibility. That said all of those licenses seem to be either trunking systems or attached directly to various departments that are not OEM who operates the sirens - so possible, I'm just thinking the pager system is most likely.

jcrawfordor 10y ago

If my guess that they use their POCSAG system is right, they have four transmitter sites licensed to 350 watts each. This is beyond inexpensive equipment, but not beyond what you can buy from a ham radio shop and then 'unlock', for example. But of course it's a paging system, so the goal is strong one-way coverage to small devices in buildings and such. The sirens are all outdoors and probably all have generous fixed antennas installed, so you wouldn't need nearly as much power to get a message to them. I assumed that the hackers injected their command via radio, which I still think is likely based on getting the FCC involved, but with POCSAG involved there's definitely another possibility. A lot of pager systems might have a fairly exposed way to send in messages - a phone number you can call, an email address, perhaps a poorly secured web interface. The hackers might have figured out what pager numbers the sirens respond to by listening in and then sent their message via "legitimate" means like an email-to-pager gateway.

zorm 10y ago

There were mentions of the repeater system last night, so my guess is they transmitted weakly somewhere and the repeater happily repeated it out to activate all the sirens. You can do this pretty trivially with HAM gear, although some may require small modifications to allow transmitting on the necessary frequencies. You can also often buy the equipment on ebay ready to go.

cyberpunk 10y ago
I didn't see that got a link? I sort of felt (in my ignorance of such systems) that this would have been somehow relayed / repeated instead of being a broadcast across an entire city but I didn't want to speculate as I'm clueless on this kind of tech. I know it's a nuisance, but this is the sort of thing I daydreamed about doing when I was 13 so I can't help but be kind of entertained by it (at least while the only fallout appears to be knocking people out of bed).
jcrawfordor 10y ago
The city has licenses for repeater-equipped public service frequencies, so it's definitely a possibility. That said all of those licenses seem to be either trunking systems or attached directly to various departments that are not OEM who operates the sirens - so possible, I'm just thinking the pager system is most likely.