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Toll fraud - through Embedded voicemail (CXi)

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Jakt99

Technical User
Dec 19, 2009
236
AU
Hi All

Have a real doosey that has me at a loss.

Background first
The system in question is a CXi runnuning on mcd 4.0 sp1 with one basic rate connections and couple of IP handsets (5312) and auto Atendant not implemented. The only voice mailboxes configured on the device are:
- mailbox 0
- admin mailbox 999
- And two user mailboxes for above handsets
- 4 VM ports are active

Zero is used for dialling an external line and 9 for an operator.

Misc programming such as DISA, account codes, sys speed dials not implemented.

Acess to the web interface is behind a corporate firewall block from external sources.

The customer is using the box for staging and design purposes, not a production box.

The customer has numerous CXi chassis' in the field and uses above system to test out functions and features before deploying to the field and has standardised configuration where possible across the board (COS, COR, number scheme etc) and naturally loaded in above system.

Situation:
I received a call to assist with investigating international calls being made from the embedded voicemail system, during the early hours of the morning. Verified by reviewing the SMDR logs (logs read smdr .....) and telco billing. Note: SMDR is also setup to capture internal and incoming calls, so we can see a trail into voicemail and out.

Naturally the 1st place I reviewed was ARS and COR applied to the embedded voicemail ports to ensure that voicemail could not make an international call. All confirmed that its configured to block, and I even went to the extend of applying the same COR of voicemail ports to a handset and dialled the number shown in the smdr log, and received the usual "Access denied" message....

The next area I reviewed was voice mail.

- Voicemail options, supervised transfer is enabled and restricted from dialling all numbers
- None of the user voice mailboxes have a dial 0 for operator configured or cell phone / fax transfer configured
- 6 digit passcodes enabled on all mailboxes, none at default.

Next I looked a mailbox 0 and the only concerned was the dial 0 for operator was configured as 0. My 1st through was if a hacker got to the default AH AAmessage, waited he/she would be transferred to zero which dials an external line then began dialling (somehow) the international number. But I can't seem to make this work either.

I ran out of time Friday to investigate further, my next steps is:
- To configure a mailbox with a cell phone transfer and put in the international number in question and actually see if the CXi is blocking voicemail ports calling out.
- Play with the maximum digits dialed form, currently set to unlimited for all CORs and rstrict capacity there.

Can anyone suggest other areas to investigate or review or has come across something similar? Have I missed something obvious......
 
1st thing..make sure the admin password has been changed from the default as well as the manager password.

2nd.. If the voicemail ports don't dial out for message notification, cell phone, fax,etc... remove their interconnect from the Trunks.

I had someone hack into an old EM card on the sx200 and use a Toll Free access international dialing number to make international calls. Since the ports didn't need to dial out for anything, I restricted them to internal only. The hackers used a menu tree box to setup the external dialing which I had disabled in the EM programming.

"The only problem with common sense is that it's not that common
 
Thanks Jonmyk

Re Admin and Manager passcodes: Forgot to mention were changed from default, Very valid point / area of attack.

RE Interconnection restrictions suggestion: Everything set at default "1". As you pointed out, don't want to change / restrict over all as production systems, some user mailboxes utilise transfer to cell phone facility.




 
When changing passcodes, most people forget to change the Technicians passcode. This passcode is even higher access than admin and is usually default.

Did you check your Speedcall table for the number dialed.

Is the direct trunk select FAC guessable? In this case, I would expect trunk 1 to be used as opposed to whatever is programmed first in your trunk group. I very big clue.

What type of trunks are connected. Digital or analog? What are the ARS timeout parameters if Analog?

**********************************************
What's most important is that you realise ... There is no spoon.
 
Thanks kwbMitel


Arr Technician passcode not heard of that one before....Can you elaborate on, only aware of Admin and Manager.

No speddcall tables

Direct trunk select FAC: Will check out. From memory?? I think the client has disabled in COS and removed from FAC form

Trunks: Only one Basic rate
 
The technicians passcode is used to activate and deactivate certain features on the system.

I hesitate to post the passcode for obvious reasons. There are documents at Mitel Online that can provide the info.

This doc has some good info.
**********************************************
What's most important is that you realise ... There is no spoon.
 
KwbMitel

Thanks again.

I'll log into MOL and dig out relevant detail

 
KwbMitel

Found technician passcode details on MOL.
Thanks again, will have a play today....

Its frustrating not to have known about this technician account. We all endeavour to lock down systems the best of our ability. Do the right thing by customers.....

I have received numerous bulletins on implementing safe guards to minimise VM toll fraud from mitel support over the years and here is a back door account, with a higher level of control than the admin account, assigned a default passcode, which they have never bothered to mention or talk about......




 
Hi kwbMitel

Thanks for info again on technician passcode....But how do you change the passcode???Tried using option 6 passcode changes are for admin and manager only ????
 
Yes, I do.
It's in a hidden menu.
I'm pretty sure what follows is correct. From memory.

Enter passcode
press digit 9
>Prompt"enter technicians option code"
17271
>Prompt"enter technicians option code"
{enter passcode]
>Prompt"enter technicians option code"
{Confirm Passcode}
>Prompt "Passcode has been changed"

**********************************************
What's most important is that you realise ... There is no spoon.
 
I've become something of a TF expert as we had some major TF coming out of one of our switches this year.

What I had found was some mailboxes had the default or an easy to guess passcode and the hackers had put the dlist on the voicemail mailbox. What they were doing then was dialing that extension via our AA OOH, getting to that extension via dial by name and then simply pressing a node on the dlist to dial to wherever they wanted. There is a way of finding out which mailboxes have got this setup but I shouldn't really put that information on here. Of course ARS could of prevented that, but the way our kit was configured, restricting international dialing would of become another nightmare.

I also found that our vendor ALLOWED operator assisted dialing, it took them 3 months to stop that no matter how much I pestered them and threaded with legal action.

We also increased the number of digits for a mailbox from 4 to 6, and enabled mailbox lockout. The lockout feature is good as it really limits the hacker to 3 attempts, and hopefully the user will then come to you to let you know their mailbox is locked, at which point you can go in, check their settings and create a random passcode for them.

If you want to know how to find out if a mailbox has that dlist configured without changing the passcode of every user, drop me a message.
 
Firstly thanks again kwbMitel
Was able to change technician pass-code. WOW what a way to go about it....My curiosity appetite would like to know what other function codes can do....But thats why the design engineers tell no one nothing (Curiosity kills the cat...system.....Play smart and leave it at that)

MitelAvaya
Have implemented lockout and increased passcode length to 6 digits.

Would like to know how to check dist lists. Will drop you a note. This would be a nice feature to add to the web interface, even just be able to view including cell mobile and fax diverts.

 
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