VOIP voicemail hacked aka DISA toll fraud
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@scottalanmiller said in VOIP voicemail hacked aka DISA toll fraud:
@Donahue said in VOIP voicemail hacked aka DISA toll fraud:
There are only 10k 4 digit pin combo's anyways. It's never been a very secure mechanism, and without some sort of lockout for too many bad guesses, it's trivial to break any pin.
Assuming it's a four digit limit. If so, that's on Cisco, at least that part of it.
Which honestly wouldn't be surprising. . .
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On this subject, Twilio blocks almost everything not NANPA by default.
I just checked, this is all you can call
North America: US & Canada
South America: Brazil
Europe: France, Germany, United Kingdom
Asia: India, Israel, Japan
Oceania: Australia/Cocos/Christmas Island -
The documentation for the Cisco Unity system says there are policies that can be set for the voicemail pin, including minimum length, the duration an account is locked, if an admin has to manually unlock an account etc.
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@JaredBusch said in VOIP voicemail hacked aka DISA toll fraud:
This is one of the reasons I never setup automatic funding on SIP trunks.
The account will run out of money before things get super out of control.
I have adopted this same belief. My customer who I managed their phones asked me if we could just setup auto billing - I told them yes, but then they were at the mercy of hackers if they were hacked and how high the bills would be.
In this case, the customer decided that 4 months of normal billing would be tolerable to loose if hacked versus having to refresh the money more often than 3 times a year.i.e. let's say they spend $50/m normally. They will preload the account with $200 which should last 4 months. Now they only have to add more money three times a year, not monthly.
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@Dashrender said in VOIP voicemail hacked aka DISA toll fraud:
@JaredBusch said in VOIP voicemail hacked aka DISA toll fraud:
This is one of the reasons I never setup automatic funding on SIP trunks.
The account will run out of money before things get super out of control.
I have adopted this same belief. My customer who I managed their phones asked me if we could just setup auto billing - I told them yes, but then they were at the mercy of hackers if they were hacked and how high the bills would be.
In this case, the customer decided that 4 months of normal billing would be tolerable to loose if hacked versus having to refresh the money more often than 3 times a year.i.e. let's say they spend $50/m normally. They will preload the account with $200 which should last 4 months. Now they only have to add more money three times a year, not monthly.
Correct. that is how I handle it wit clients. they determine how much to pre-load, but I never let them turn on auto-renew without signing a waiver of liability. So far no one has signed it.
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Most of our customers control their own accounts, so if they pre-load or not doesn't come through us. But we never recommend just having it auto-load.
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@scottalanmiller said in VOIP voicemail hacked aka DISA toll fraud:
Most of our customers control their own accounts, so if they pre-load or not doesn't come through us. But we never recommend just having it auto-load.
Some do, some do not. But when it is all set up the first time they are told that it is not allowed without signing a waiver that charges are not my problem.
Of course one could change it afterwards, but none have yet.
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@DustinB3403 said in VOIP voicemail hacked aka DISA toll fraud:
The documentation for the Cisco Unity system says there are policies that can be set for the voicemail pin, including minimum length, the duration an account is locked, if an admin has to manually unlock an account etc.
After the fraud, the VOIP provider has implemented stronger policies for PIN's now. I will be talking to them about implementing some sort of stoppage on international calls after they hit a certain limit. We are also going to take a hard look at turning off international calling and/or picking specific countries that we need to contact.
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@scottalanmiller said in VOIP voicemail hacked aka DISA toll fraud:
Most of our customers control their own accounts, so if they pre-load or not doesn't come through us. But we never recommend just having it auto-load.
With this customer - it's kinda 50/50. When I get the renewal notices (and they get them too) i remind them to log in or give me a CC to add more money.
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@magicmarker said in VOIP voicemail hacked aka DISA toll fraud:
@DustinB3403 said in VOIP voicemail hacked aka DISA toll fraud:
The documentation for the Cisco Unity system says there are policies that can be set for the voicemail pin, including minimum length, the duration an account is locked, if an admin has to manually unlock an account etc.
After the fraud, the VOIP provider has implemented stronger policies for PIN's now. I will be talking to them about implementing some sort of stoppage on international calls after they hit a certain limit. We are also going to take a hard look at turning off international calling and/or picking specific countries that we need to contact.
Yeah, that's pretty much all you can do. Police your own people, investigate why voicemail was allowed to do as much as it was (maybe getting off of Cisco is part of your solution, not sure how many systems are really susceptible to voicemail attacks in this manner), find out how voicemail was accessed without access to something more, have the vendor lock down anything that could explode usage that isn't needed like calls to countries that you'd never made, and put in some kind of rate limiting.
There is always going to be some risk, but you can reduce it in both likeness of happening again, and in the scope of potential damage.
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@JaredBusch is FreePBX susceptible to this kind of attack? On none of ours is voicemail ever the first line of defense, first of all. But even if someone breached voicemail, I don't think that they can use that to make calls. I know some systems do, and Cisco is pretty renowned for lacking security, and I might easily be overlooking something, but I feel like this isn't a normal attack vector outside of the Cisco world.
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@scottalanmiller said in VOIP voicemail hacked aka DISA toll fraud:
@JaredBusch is FreePBX susceptible to this kind of attack? On none of ours is voicemail ever the first line of defense, first of all. But even if someone breached voicemail, I don't think that they can use that to make calls. I know some systems do, and Cisco is pretty renowned for lacking security, and I might easily be overlooking something, but I feel like this isn't a normal attack vector outside of the Cisco world.
IIRC it is possible but disable by default.
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@scottalanmiller said in VOIP voicemail hacked aka DISA toll fraud:
@JaredBusch is FreePBX susceptible to this kind of attack?
I was wondering the same thing.
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@scottalanmiller Jared Busch finished about a liter of sake last night. Ask him later.
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@scottalanmiller It may not matter here but we have an old Cisco system and our pins are 7 digit so it seems it is customizeable.
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By default it does not work unless someone goes into this hard to find setting and populates it.
If you dial into my voicemail with my password and hit option 3 for advanced options, the only valid choice is option 5 to leave a message for another extension. There is no way to break out of it. Hitting option 4 kicks it back to the initial mailbox menu.
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@JaredBusch that's what I thought. As I look at our systems, none seem to have any susceptibility to this kind of attack. Maybe Cisco doesn't out of the box and someone enabled this ridiculousness? That seems unlikely, but who knows.
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For me, I do auto funding but only in the range of $50-80 per hit.
This way I get alerts on my iPhone from my c/c every time a VOIP replenish charge goes through.I also have International calls disabled.
