Re: TTY phone fraud and abuse

["Steven M. Bellovin" <smb () research att com>]

In message <4079F583.3010200 () outblaze com>, Suresh Ramasubramanian writes:
> [4/12/2004 4:49 AM]  Steven M. Bellovin :
>
> > Naturally, miscreants (to use robt's terminology) try to find ways to 
> > make such calls from the U.S. more cheaply.  Sometimes, this involves 
> > hacking PBXs, other times, it involves subscription fraud, or a variety 
> > of other kinds of misbehavior.  The responses are similar to those we 
> > use on the Internet -- traffic analysis (similar to looking at 
> > NetFlow), blacklisting calls to certain countries from, say, pay 
> > phones, etc.
>
> There is another class of people who route calls out from the USA to 
> India (or elsewhere) using VOIP, terminate the calls at an unauthorized 
> (that is, not run by a licensed telco) exchange in india, and then route 
> the calls out through the local pstn or mobile network.
>
> Quite a few of the "call $asian_country for cheap" phone cards you find 
> at ethnic grocery stores seem to work on these lines.
>
> The local telco doesn't see a red cent of any settlement charges when 
> this happens.  Local telcos are, of course, all against this, and use 
> any and every excuse to get these exchanges busted - a procedure that 
> typically involves having the local police raid the exchange.

Yes.  Depending on the countries and telcos involved, this is either 
illegal or "irregular" network access.  Other schemes involve call-back 
(with the Internet as the signaling channel -- I first heard of that 
being used in 1994, when most people outside our business had never 
heard of the Internet) or calling through a third country if the 
difference in rates makes that profitable.

                --Steve Bellovin, http://www.research.att.com/~smb