Rob wrote:
So I read this /. article:
"We already knew the FBI can secretly listen in to car conversations by activating microphones of systems like OnStar. A new Mafia court case suggests that the FBI can do the same thing to cell phones. The judge's opinion and some background information [pdf] are available for reading online. The most disturbing thing? According to the judge, the bug worked even if the phone appeared to be 'powered off.' Anyone up for an open-source handset already?"

Now, the idea that a cell phone could easily be turned into an open mic with a little software mod is not a new idea. But now that people are known to actually be doing it, that just fuels my existing paranoia. So my thought is this:

Is there a way I can lawfully monitor the emissions from MY cell phone to determine if it is transmitting audio when I'm not using it? That sure would be handy.

Rob

You just need an RFID Wallet / portable Faraday cage to put the phone in when you know you have it off. Alternatively, one could probably come up with a RF detector to slip around or near the antenna and pick up radiated RF from the antenna and alert you that the phone is transmitting.

RF detectors are incredibly simple devices, from an electronic perspective. Usually just a diode and a capacitor and some form of electronic switch (a few transistors for voltage/current gain). For WiFi, these detectors have to operate at in excess of 11 MHz, but since we have transistors and diodes that work into the gigahertz, that is also a non-issue.

Catonic wrote:

Rob wrote:
So I read this /. article:
"We already knew the FBI can secretly listen in to car conversations by activating microphones of systems like OnStar. A new Mafia court case suggests that the FBI can do the same thing to cell phones. The judge's opinion and some background information [pdf] are available for reading online. The most disturbing thing? According to the judge, the bug worked even if the phone appeared to be 'powered off.' Anyone up for an open-source handset already?"

Now, the idea that a cell phone could easily be turned into an open mic with a little software mod is not a new idea. But now that people are known to actually be doing it, that just fuels my existing paranoia. So my thought is this:

Is there a way I can lawfully monitor the emissions from MY cell phone to determine if it is transmitting audio when I'm not using it? That sure would be handy.

Rob

You just need an RFID Wallet / portable Faraday cage to put the phone in when you know you have it off. Alternatively, one could probably come up with a RF detector to slip around or near the antenna and pick up radiated RF from the antenna and alert you that the phone is transmitting.

RF detectors are incredibly simple devices, from an electronic perspective. Usually just a diode and a capacitor and some form of electronic switch (a few transistors for voltage/current gain). For WiFi, these detectors have to operate at in excess of 11 MHz, but since we have transistors and diodes that work into the gigahertz, that is also a non-issue.

Interesting thought, however, my understanding is that the phone will continue to "talk" to cell towers when I'm not using it. In that case it would still be transmitting RF but not sound. I would think the RF detector would need to be able to discern between data and voice RF content.

Rob

Rob wrote:

Interesting thought, however, my understanding is that the phone will continue to "talk" to cell towers when I'm not using it. In that case it would still be transmitting RF but not sound. I would think the RF detector would need to be able to discern between data and voice RF content.

Rob

Not necessarily. One of the nice parts about packetized voice is that it requires packets be sent on a period basis. Thus a phone that is sending/recieving packets from the cell network won't be transmitting as often as one that is involved in a phone call. Just hold your cell phone up to your cheap PC speakers for a demonstration. You're hearing rectified RF at that point, but you only process it as interference.

Rob wrote:
Is there a way I can lawfully monitor the emissions from MY cell phone to determine if it is transmitting audio when I'm not using it? That sure would be handy.

Some thoughts about this here:

Simple ways to tell if your cellphone is acting strange