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Suspected phone tap

Discussion in 'Electrical Engineering' started by Foxtrot, Feb 19, 2008.

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  1. Foxtrot

    Foxtrot Guest

    I have never been a conspiracy theorist but I suspect that a particular
    group of people may try to tap my landline.

    I am in the UK and access to my phone wires is quite easy because I live
    in a block of flats. There are various oblong concrete covers for the
    BT and VirginMedia lines to the flats.

    Currently I use VirginMedia for phone service.

    I wonder if a tap which juts picks up the signal modulation on a line
    but does not interrupt it can be detected at all.

    Can I perform any checks?
    Can I ask VM to do any checks?

    As I am dealing with some odd folks, I would like to have the line
    checked regularly but would VirginMedia be prepared to do this?
     
  2. Palindrome

    Palindrome Guest

    It is illegal to gain access to another person's telephone under Section
    1 of the Regulation of Investigatory Powers Act 2000 (RIPA). If you have
    good reason to suspect that your calls are being intercepted, then
    contact the police.

    There are no meaningful checks that you can do, or VM would do. Other
    than visually inspect whatever bits of your telephone line might be
    accessible to you.

    If you are worried, but don't think that you have enough evidence to go
    to the police, then use a mobile phone or internet phone. Those are
    rather more difficult for an unspecified group of people to intercept.
     
  3. PeterD

    PeterD Guest


    Properly done taps are virtually impossible to detect.
     
  4. If the police/spooks are doing it, they'll do it in software at the
    exchange so there'll be nothing to see.

    http://spectrum.ieee.org/jul07/5280
    documents one rather high-level recent case.

    Theo
     
  5. Palindrome

    Palindrome Guest

    They aren't easier for "unspecified groups of people" to do. Government
    agencies and others authorised to intercept communications are very well
    "specified".
     
  6. Guest

    | On Tue, 19 Feb 2008 15:47:02 GMT, Foxtrot <>
    | wrote:
    |
    |>I have never been a conspiracy theorist but I suspect that a particular
    |>group of people may try to tap my landline.
    |>
    |>I am in the UK and access to my phone wires is quite easy because I live
    |>in a block of flats. There are various oblong concrete covers for the
    |>BT and VirginMedia lines to the flats.
    |>
    |>Currently I use VirginMedia for phone service.
    |>
    |>I wonder if a tap which juts picks up the signal modulation on a line
    |>but does not interrupt it can be detected at all.
    |>
    |>Can I perform any checks?
    |>Can I ask VM to do any checks?
    |>
    |>As I am dealing with some odd folks, I would like to have the line
    |>checked regularly but would VirginMedia be prepared to do this?
    |
    |
    | Properly done taps are virtually impossible to detect.

    Improperly done taps could be detected by means of a loss of signal or a
    reflection signal coming back. A well done tap would capture a miniscule
    level of signal via high impedance loading, and there is no way to see
    that by any means. What little reflection it might have would pale in
    comparison to the typical reflections along the wire at various patch
    panels and such. So you wouldn't know it was there.
     
  7. Guest

    | In article <[email protected]>,
    |
    |> I have never been a conspiracy theorist but I suspect that a particular
    |> group of people may try to tap my landline.
    |
    | You're not that MI5 paranoid spammer are you?

    The MI5 spammer is already convinced his phone is tapped. If it was not
    before, it surely is now, anyway.
     
  8. Palindrome

    Palindrome Guest

    That would have been an analogue cell phone. The OP is in the UK, where
    these were phased out some time ago. IIUC, they will soon all be gone
    from the USA, too.

    It is possible to intercept digital cellphone traffic, but decrypting
    it, without cloning the phone's key (which needs physical access to the
    phone) is rather more difficult than tapping a landline.
     
  9. Ivor Jones

    Ivor Jones Guest

    [snip]

    : : It is possible to intercept digital cellphone traffic,
    : : but decrypting it, without cloning the phone's key
    : : (which needs physical access to the phone) is rather
    : : more difficult than tapping a landline.

    Read this article, posted elsewhere in this thread, to see how someone
    recently did exactly that:

    http://spectrum.ieee.org/jul07/5280


    Ivor
     
  10. Palindrome

    Palindrome Guest

    The article rather proves my point."Major network penetrations of any
    kind are exceedingly uncommon. They are hard to pull off, and equally
    hard to investigate."
     
  11. The simplest attack on GSM is sniffing it over-the-air.

    It's not easy, but the A5 cipher used by GSM (2G) has various
    vulnerabilities and there are some people working on a useful GSM cracker:
    http://events.ccc.de/camp/2007/Fahrplan/events/2015.en.html
    Barkan, Biham and Keller have presented a realtime practical attack on GSM
    based on breaking A5:
    http://cryptome.org/gsm-crack-bbk.pdf

    KASUMI in UMTS (3G) as yet doesn't have any practical attacks.

    Theo
     
  12. Palindrome

    Palindrome Guest

    The challenge was to my words, ".. use a mobile phone or internet phone.
    Those are rather more difficult* for an unspecified group of people to
    intercept." *Than a land line.

    I would suggest that those words are correct. Specified groups, such as
    Government Agencies, are a different matter.
    Thank you. I would suggest, "not as easy as tapping a land line" as
    alternative wording.
    The "unspecified group" isn't likely to contain experts on crypto.

    The scope of this thread was the suspected tapping of a landline phone
    going to a flat. Generally extremely easy to do, needing little
    expertise or expensive equipment. The suggestion was to use a mobile
    phone - which, as the OP is in the uk, means a phone with an encrypted
    digital data stream. Intercepting that would need a great deal of
    expertise - it would be far easier to resort to other methods, eg
    eavesdrop on the sound signals in the room(s).
     
  13. PeterD

    PeterD Guest

    considering that virtually all phone lines have stubs along their
    route, echos and reflections are always expected and are also
    unpredictable in nature.
     
  14. Guest

    | wrote:
    |>| Properly done taps are virtually impossible to detect.
    |>
    |>Improperly done taps could be detected by means of a loss of signal or a
    |>reflection signal coming back. A well done tap would capture a miniscule
    |>level of signal via high impedance loading, and there is no way to see
    |>that by any means. What little reflection it might have would pale in
    |>comparison to the typical reflections along the wire at various patch
    |>panels and such. So you wouldn't know it was there.
    |
    | Why would anyone do an analog wiretap?

    They would if the line is analog. But even if digital, a poor tap can
    still be detected by using a TDR which would be pushing an analog signal
    on the wire and watching what comes back.
     
  15. It's cheap, easy, fast, and convenient for those who want to tap a line
    without going through the official legal channels, red tape and associated
    paperwork that would usually stop you anyway.
     
  16. RFI-EMI-GUY

    RFI-EMI-GUY Guest

    Jim wrote:
    (snip)

    I have had three occasions in past where my phone line was bridged to
    the premises of another subscriber. Once in an apartment where due to a
    remodeling error, the neighboring apartment had a phone jack accessible
    to my circuits. He used the line freely making toll calls. Next I had a
    house in the back woods of Tallahassee where the circuits were poor. A
    couple of times the phone repairmen bridged my circuit with a neighbors
    looking for a "good pair". This last time a neighbor moved into a vacant
    residence near mine, plugged in her phone and had instant service, on MY
    line. The phone repairman volunteered that the documentation was very poor.

    The cabinets and pedestals in this neighborhood are unlocked and often
    left open to the elements.

    --
    Joe Leikhim K4SAT
    "The RFI-EMI-GUY"©

    "Treason doth never prosper: what's the reason?
    For if it prosper, none dare call it treason."

    "Follow The Money" ;-P
     
  17. Clint Sharp

    Clint Sharp Guest

    Umm, sorry, nil points and misleading, you are MI5 and I claim my 5
    pounds.

    There are off air intercept systems available to people with the right
    credentials and/or money that can decrypt the data real time. The system
    manufacturers (Ericsson spring to mind for some reason ;-)) offer
    intercept systems although I suspect you'd need to be very definitely
    government/law enforcement to get one legally.

    Best of all carrying a powered cell phone can locate you to under 100
    metres depending on the number of cells that can 'see' you and a few
    other factors (terrain, buildings etc.) It's been trialed and tested for
    emergency services use in London with good results but then disappeared
    without much discussion, wonder why that was!
     
  18. Ron Lowe

    Ron Lowe Guest


    If I felt the need of a secure phone system, I would set up a secure private
    VoIP network.

    At my end:
    1) Set up an Asterisk server on my LAN;
    2) Configure an IP phone to register with it;
    3) Configure a secure VPN gateway to accept incoming connections.

    At the other end(s):
    1) Configure a VPN client box to establish a secure tunnel to my LAN's VPN
    gateway;
    2) Configure an IP phone to register with my asterisk box over the VPN.

    If you choose a good enough VPN implimentation, then I think it would be
    pretty secure.

    If you want to be extra-paranoid, then....

    If I was trying to hide from Government Agencies, I'd probably find an Open
    Source VPN soloution which I was confident had no back doors. I'd not
    trust a VPN box from ( for example ) a Big American Networking Corporation
    not to have been leaned on to provide back-door access to their VPNs by the
    American Security Services. After all, I'm talking about the kind of
    corporations that are complicit with other unpleasant regimes in the world
    to police their populations, in order to gain global market share. If
    they're prepared to roll over for foreign governments, then I have no doubt
    they would be even more complicit with their domestic security services.

    But perhaps I'm being paranoid, and need to adjust my tinfoil hat :)
     
  19. Clint Sharp

    Clint Sharp Guest

    Is it fibre to the home though? I thought it was just fibre to the
    street cabinet and then coax to the home?
     
  20. Palindrome

    Palindrome Guest

    Oh, it would be possible to locate the OP to within a few feet, at most.
    I suggested using it /in his flat/ rather than use the landline.

    As for the "people with the right credentials" - there is no suggestion
    by the OP that such people are involved. For others, the only real
    chance is to get hold of the phone and clone it.

    And what you suggest is still far, far more difficult than tapping a
    landline.

    I presented a simple argument - that using a mobile phone instead of the
    landline would be harder to tap. Which your words support - other than
    the "nil points" rubbish.
     
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