Long Distance

Last update:

  The Improperly Configured PBX

An improperly configured PBX can lead to thousands of dollars in losses.  This is something that a PBX administrator can and should check for themselves.

Here is an example of how I have personally seen the fraud in action. 

A caller dials into your systems, often via your 800 numbers.  If voice mail auto attendant answers the caller will either cause the system to hang up on them by pressing invalid keys or by simply waiting for the system to time out on them and hang up.  If an operator answers, the call will simply not say anything until the operator believes there is no one there and hangs up the call.

This is where the improperly configured PBX can be used against you.  Once the auto attendant or operator hangs up, if the PBX is not configured properly, there may be a second dial tone provided by the PBX or perhaps just silence, but the caller has the opportunity to dial "9" and a number and dial back out of your system.  You then, pay for their call.  Twice: once on the 800 number coming into your system and also for the outbound call.

In the above example, there are two things that are improperly configured.

1. The PBX is not disconnecting the call when the internal answering point hangs up. (Auto Attendant, Voice Mail, Operator or User.)
    

2. The PBX does not have the proper restrictions to keep one trunk from dialing back out on another trunk.

This is something an administrator can easily check for.  Simply dial your own 800 number talk to your operator and ask them to simply hang up on you.  Once the operator has hung up, you should be disconnected within a brief amount of time.  While you are waiting for the disconnect, press the number for your outside access (usually "9") to see if you get secondary dial tone.  If you do then try and dial any outside number.  This will check for two things, that the line actually disconnected and if not that the line you came in on is still restricted.

Now do the same for your after hours auto attendant and your voice mail system.

When you do this test, you should do it from a display phone.  Watch for changes on the display to be sure that the line actually did disconnect and you are not just dialing another outside call.

You should also bear in mind that some telephone systems allow you to dial additional codes for outbound access that you may not even be aware of.  Such as trunk group access codes and individual trunk codes.  You should check with your PBX vendor to see if your PBX uses such codes and document their response.

Remember, if there is any question as to the security of your PBX, then it is better to hire a consultant than to risk loosing thousands of dollars in a single weekend.