Sjur Usken

Views on new technologies and business opportunities from Sjur Usken

Another day, another VoIP fraud (just 13 000 USD..)

This time it was h.323 on a Cisco CallManager which was exploited in some ways. My personal guess is just bad configuration, but maybe there also is a bug in it as well.From a mailing list:

A company we work closely with, but is not our customer, had their Cisco
Call Manager hacked due to some h.323 vulnerability that I don’t have
full details on yet.  There were a number of calls placed to:


My findings indicate these are Globalstar satellite numbers that cost
somewhere between $4 and $7/minute to call, depending on carrier.  The
victim’s carrier is billing them at $6.50.  The total bill for the event
is around $13k.  This is a small company that can’t really afford this.

If I had a small company and connected to a carrier, I would demand credit limits. It is the same as I would not have a 1 million credit limit on my credit cards. Check with your VoIP carrier that he has effective credit limits!

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