Live data from Hacker News

Americans’ Cellphones Targeted in Secret U.S. Spy Program

online.wsj.com

41–50 of 73 posts

Re: Americans’ Cellphones Targeted in Secret U.S. Spy Program

#41

I think cell antennas have unique identifiers. If true, can you detect when you connect to a tower that isn't your usual tower in your usual geographic location (assuming you're being targeted at home, for example). And if there is indeed a unique id, can the fake cell take the id of a real cell and still work with the cellphone company, or would it need the cooperation of the cellphone company? (for example, the cel…

I wonder how much drag that antenna has.

Re: Americans’ Cellphones Targeted in Secret U.S. Spy Program

#43

I think cell antennas have unique identifiers. If true, can you detect when you connect to a tower that isn't your usual tower in your usual geographic location (assuming you're being targeted at home, for example). And if there is indeed a unique id, can the fake cell take the id of a real cell and still work with the cellphone company, or would it need the cooperation of the cellphone company? (for example, the cel…

wouldn't have to relay calls, collecting numbers shouldn't take that long

Re: Americans’ Cellphones Targeted in Secret U.S. Spy Program

#46
post #7

Here are some excerpts from the WSJ paywalled article: Cellphones are programmed to connect automatically to the strongest cell tower signal. The device being used by the U.S. Marshals Service identifies itself as having the closest, strongest signal, even though it doesn’t, and forces all the phones that can detect its signal to send in their unique registration information. Even having encryption on one’s phone, su…

In addition to the egrigious complaints citizens could make, wouldn't telecoms and cellphone manufacturers have grounds to sue over this? It sounds like these boxes are actively disrupting or reducing cell-phone service reliability by tricking devices to connect to them, despite not being a good tower.

Ultimately, it's the government that mediates the dispute. They're the government's airwaves and you (the cell phone provider) receive a license to use them. I haven't read the relevant FCC regulations, but they can easily say "cell phone service is secondary; law enforcement is primary".

There is precedent: amateur radio operators can use any means available to them to transmit life-critical messages when licensed methods/frequencies don't work. If that was to set up a fake cell phone tower and get phones to connect, then one could argue that one was using the frequencies legally. (IANAL; don't do this and say I said it was OK. The usual case is something like using your amateur radio to contact the coast guard if your ship is sinking.)

Re: Americans’ Cellphones Targeted in Secret U.S. Spy Program

#47

I think cell antennas have unique identifiers. If true, can you detect when you connect to a tower that isn't your usual tower in your usual geographic location (assuming you're being targeted at home, for example). And if there is indeed a unique id, can the fake cell take the id of a real cell and still work with the cellphone company, or would it need the cooperation of the cellphone company? (for example, the cel…

GSM contains half-baked kludge to make passive tracking of phones impractical. Phone transmits it's IMSI only when network asks it to (eg. when connecting to network) and then uses random session identifier ("TMSI") for normal traffic. So if you want to reliably identify and track particular phone or subscriber without assistance from network, you have to actively MitM the network.

Re: Americans’ Cellphones Targeted in Secret U.S. Spy Program

#48
I understand that you can sniff IMSI without being a recognized carrier. But to actually get a cell phone to join your tower – don't you need the carrier's keys to be able to authenticate during the tower handshake? (iOS 5+ warns about unencrypted tower connections, so presumably these have to be authenticated UMTS?)

If so, should we expect that the carriers surrendered their keys to law enforcement to allow them to run fake cell towers that authentically emulate their networks?

Re: Americans’ Cellphones Targeted in Secret U.S. Spy Program

#49
Last year a Cessna (a Skylane or Stationair) orbited the around central SF for several hours over 3 or 4 days. The edge of the track was right over my block. It would drone by every few minutes. It did not have a removed door or anything that would indicate camera platform. The constant orbit wouldn't make sense as an photographic mapping platform.

It was not on flighttrack, no ADS-B info, and too high to see the N number.

Re: Americans’ Cellphones Targeted in Secret U.S. Spy Program

#50
> A Justice Department official would neither confirm nor deny the existence of such a program. The official said discussion of such matters would allow criminal suspects or foreign powers to determine U.S. surveillance capabilities.

This is the go-to defense for surveillance secrecy. However, not discussing such matters allows criminal officials to abuse these powers without repercussion.

Post reply on HN