SIP evesdropping/security

Discussion in 'VOIP' started by Martin 53N 1W, Aug 13, 2004.

  1. For SIP:

    Is there a secure version?

    Can SIP calls be evesdropped by someone else on the lan or internet??

    Is there an encrypted version?

    Thanks,
    Martin


    --
    ---------- OS? What's that?!
    - Martin - To most people, "Operating System" is unknown & strange.
    - 53N 1W - Mandrake 10.0.1 GNU Linux
    ---------- http://www.mandrakelinux.com/en-gb/concept.php3
     
    Martin 53N 1W, Aug 13, 2004
    #1
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  2. Martin 53N 1W

    Kurt Jaeger Guest

    Hi!

    In article <WqVSc.3944$>,
    Martin 53N 1W <> wrote:
    >For SIP:
    >
    >Is there a secure version?


    >Can SIP calls be evesdropped by someone else on the lan or internet??


    There are two parts in SIP: The control channel (SIP) and
    the signal itself (RTP).

    >Is there an encrypted version?


    For RTP: SRTP

    See e.g.: http://www.vovida.org/protocols/downloads/srtp/

    --
    MfG/Best regards, Kurt Jaeger 16 years to go !
    LF.net GmbH fon +49 711 90074-23
    Ruppmannstr. 27 fax +49 711 90074-33
    D-70565 Stuttgart mob +49 171 3101372
     
    Kurt Jaeger, Aug 13, 2004
    #2
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  3. Martin 53N 1W

    Steve Blair Guest

    Martin 53N 1W wrote:
    > For SIP:
    >
    > Is there a secure version?
    >

    There is sRTP for the media stream.

    > Can SIP calls be evesdropped by someone else on the lan or internet??

    Yes provided you have access to the data. Ethereal can capture,
    decode and manipulate the media.
    >
    > Is there an encrypted version?

    See IETF web site for sRTP.
    >
    > Thanks,
    > Martin
    >
    >
     
    Steve Blair, Aug 13, 2004
    #3
  4. Martin 53N 1W wrote:

    > For SIP:
    >
    > Is there a secure version?
    >
    > Can SIP calls be evesdropped by someone else on the lan or internet??
    >
    > Is there an encrypted version?
    >
    > Thanks,
    > Martin
    >
    >

    Yes, it can be EASILY eavesdropped.
    To see how, download the latest ethereal - you can actually export the
    audio of a capture to an ".au" file and play it back, email it to
    friends to laugh at, etc.
     
    T. Sean Weintz, Aug 13, 2004
    #4
  5. Kurt Jaeger wrote:
    > Martin 53N 1W <> wrote:

    [...]
    >>Can SIP calls be evesdropped by someone else on the lan or internet??

    >
    > There are two parts in SIP: The control channel (SIP) and
    > the signal itself (RTP).
    >
    >>Is there an encrypted version?

    >
    > For RTP: SRTP
    > See e.g.: http://www.vovida.org/protocols/downloads/srtp/


    Thanks.


    So, unencrypted sip calls are easily eavesdropped if the link is
    accessible... (See ethereal.)


    Do the commercial VoIP providers encrypt the signal traffic?

    Or are all your VoIP internet calls 'out in the open'?


    Regards,
    Martin

    --
    ---------- OS? What's that?!
    - Martin - To most people, "Operating System" is unknown & strange.
    - 53N 1W - Mandrake 10.0.1 GNU Linux
    ---------- http://www.mandrakelinux.com/en-gb/concept.php3
     
    Martin 53N 1W, Aug 15, 2004
    #5
  6. Martin 53N 1W

    stephen Guest

    "Martin 53N 1W" <> wrote in message
    news:J4LTc.286$...
    > Kurt Jaeger wrote:
    > > Martin 53N 1W <> wrote:

    > [...]
    > >>Can SIP calls be evesdropped by someone else on the lan or internet??

    > >
    > > There are two parts in SIP: The control channel (SIP) and
    > > the signal itself (RTP).
    > >
    > >>Is there an encrypted version?

    > >
    > > For RTP: SRTP
    > > See e.g.: http://www.vovida.org/protocols/downloads/srtp/

    >
    > Thanks.
    >
    >
    > So, unencrypted sip calls are easily eavesdropped if the link is
    > accessible... (See ethereal.)
    >
    >
    > Do the commercial VoIP providers encrypt the signal traffic?


    dont think so.

    Some of the IP PBX manufacturers support encryption (e.g. Avaya. Cisco maybe
    Mitel), but i dont think there are any mature standards for this, and little
    interoperability between equipment types.
    >
    > Or are all your VoIP internet calls 'out in the open'?


    sort of - but they could only be intercepted if the "bad guy" had access to
    a link on the route between the 2 end points - exactly the same as for a TDM
    / ISDN / "normal" phone call.

    this may be similar to the arguments about just how useful https is in
    practice - i havent come across any documented instances where a credit card
    number or other info is disclosed by snooping on a conversation between end
    points - it is much easier to break into the client PC or web server and get
    at the data there.
    >
    >
    > Regards,
    > Martin
    >
    > --
    > ---------- OS? What's that?!
    > - Martin - To most people, "Operating System" is unknown & strange.
    > - 53N 1W - Mandrake 10.0.1 GNU Linux
    > ---------- http://www.mandrakelinux.com/en-gb/concept.php3

    --
    Regards

    Stephen Hope - return address needs fewer xxs
     
    stephen, Aug 16, 2004
    #6
  7. stephen wrote:
    > "Martin 53N 1W" <> wrote in message

    [...]
    >>Or are all your VoIP internet calls 'out in the open'?

    >
    > sort of - but they could only be intercepted if the "bad guy" had access to
    > a link on the route between the 2 end points - exactly the same as for a TDM
    > / ISDN / "normal" phone call.

    [...]

    Hence the weakest and most vulnerable parts are at each end on the local
    lans... (Assuming that we can 'trust' our telcos.)

    Thanks, good answer.

    Regards,
    Martin


    --
    ---------- OS? What's that?!
    - Martin - To most people, "Operating System" is unknown & strange.
    - 53N 1W - Mandrake 10.0.1 GNU Linux
    ---------- http://www.mandrakelinux.com/en-gb/concept.php3
     
    Martin 53N 1W, Aug 16, 2004
    #7
  8. Martin 53N 1W

    James Body Guest

    Martin 53N 1W <> wrote in message news:<WqVSc.3944$>...
    > For SIP:
    >
    > Is there a secure version?
    >
    > Can SIP calls be evesdropped by someone else on the lan or internet??
    >
    > Is there an encrypted version?
    >
    > Thanks,
    > Martin


    If you want hardware with SRTP support, look at the SIPURA SPA-2000.

    For UK/EU - http://www.sipura.co.uk

    For USA - http://www.sipura.com
     
    James Body, Aug 16, 2004
    #8
  9. Martin 53N 1W

    Roddaman Guest

    Steve Blair <> wrote in message news:<cfj114$df2c$>...
    > Martin 53N 1W wrote:
    > > For SIP:
    > >
    > > Is there a secure version?
    > >

    > There is sRTP for the media stream.
    >
    > > Can SIP calls be evesdropped by someone else on the lan or internet??

    > Yes provided you have access to the data. Ethereal can capture,
    > decode and manipulate the media.


    So you are saying that one's ISP or LAN admin can easily eavesdrop on
    all SIP calls, even if the SIP network one uses employs MD5 and
    MD5-sess for DIGEST authentication and encryption?

    In other words, do they not have to crack MD5 and MD5-sess before they
    can eavesdrop?

    Also, when a SIP network says they support MD5 and MD5-sess for DIGEST
    authentication and encryption, does this mean that they are encrypting
    every word of every conversation, or just the authentication process?

    Thanks in advance!

    Roddaman
     
    Roddaman, Aug 31, 2004
    #9
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